




















































riiiss T U 14 S 

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COPYRIGHT DEPOSIT. 


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Practical Automobile 
Instruction 

A Complete Cyclopedia of Practical Infor¬ 
mation for Garage Men, Chauffeurs, 
Repair Men and Automobile 
Designers and Engineers 

with 

Special Reference to-Carburetion, Ignition, 
Starting and Lighting, Motor Troub¬ 
les and Repairs, Machine Shop Prac¬ 
tice, Oxy - Acetylene Welding 
and Cutting and Carbon Remo¬ 
val by the Oxygen Process 

by 

L. ELLIOTT BROOKES 

and 

HAROLD P. MANLY 


FULLY ILLUSTRATED 


CHICAGO 

NATIONAL INSTITUTE OF PRACTICAL MECHANICS 
Publishers 




Copyright 1918 and 1917 
by 

National Institute of Practical Mechanics 


m -7 1918 



©Cl, 4497715 


'Vw f 



The Automobile Handbook, 


Acetylene Gas. The gas used in gas lamps 

is generated by water, in minute quantities, 
dropping on acetylene (carbide of calcium); 
the gas thus formed passes from the generating 
chamber into the body of the lamp and is con¬ 
sumed at the lava tips, which are placed in 
front of a highly polished mirror. The genera¬ 
tors in some cases are separated from the lamp 
itself and placed on the dashboard, or under the 
hood, a rubber hose conveying the gas to the 
lamp. 

The interior of the carbide chamber or bas¬ 
ket being more or less in contact with the water 
distribution apparatus, the parts of both appa¬ 
ratus are liable to clogging by the formation of 
lime residue in the generation of gas. If this 
residue is allowed to collect, it will have to be 
removed with a chisel, which is a ticklish opera¬ 
tion in a light construction like that of a gen¬ 
erator, especially around the water valve or 
its outlet. Acids are sometimes used to remove 
the deposit, but as they eat the metal, their use 
should be prohibited. The basket and pot 
should be thoroughly washed out after each run 
9 



10 The Automobile Handbook 

with water, the water outlets being cleaned 
with special brushes, when these are obtaina¬ 
ble, or by wires, removing all traces of lime. 
The water valve should be scraped and tested 
to see whether it seats properly, care being 
taken not to damage the valve or its seat in so 
doing. While the valve is dismounted for clean¬ 
ing it would be well to see that its stem is 
straight, and that it works with some ease in the 
threaded portion attached to the water chamber. 
The gas valves should be cleaned and should 
seat snugly, so that there will be no leakage 
past them. This applies also to the gas valves 
on the lamps. 

The best position for the generator is on the 
running-board just back of the change-gear 
quadrant, and sufficiently far out from the 
frame to allow a free circulation of air all 
around it. The generator will keep cool in this 
position and will perform its work to the best 
advantage when properly cooled. 

The system of acetylene gas lighting that is 
generally used on cars having this source of 
illumination is that making use of tanks in 
which the gas is stored under compression. 
These tanks are designed to hold 40, 60 or 100 
cubic feet of gas and from them the illumin- 
ant is carried to the various lamps through 
tubing. Attachments are furnished by means 
of which the lamps may be lighted, dimmed or 
extinguished from valves and buttons located 
on the dash or cowl of the car. 


The Automobile Handbook 11 

Acetylene Lamp System—Care of. As there 
is little night running during the winter 
months, the acetylene lighting system is more 
or less neglected, the generator being left with 
stale or partially used carbide in the chamber, 
and the residue being allowed to clog up the 
water port and the waste ports. The rubber 
lamp connections and gas-bag suffer also by de¬ 
terioration as well as the burners and gas 
valves. For the proper maintenance of the sys¬ 
tem, strict cleanliness should be maintained at 
all times, and the various parts should be ex¬ 
amined and replaced from time to time as nec¬ 
essary. The results of neglect are seen every 
spring in lime deposits which have to be remov¬ 
ed by means of a cold chisel, in porous connec¬ 
tions and in clogged burners which resist the 
cleaning wire and necessitate the scraping of 
the burners. By following the accompanying 
directions, the automobilist can depend on hav¬ 
ing his lighting system in good shape whenever 
he desires to use it. 

Acid Solutions. The electrolyte, or solution 
used in storage battery cells, is made by pour¬ 
ing sulphuric acid into distilled water until the 
specific gravity becomes 1.25. The solution be¬ 
comes extremely warm and should not be used 
until its temperature is about 60 degrees. 

Active Coil, or Conductor. A coil, or con¬ 
ductor, conveying a current of electricity. 

Adams Revolving Cylinder Motor. The 
Adams motor rated at 50 horse power has a five 


12 


The Automobile Handbook 


cylinder engine with a bore and stroke of 5% 
and 5 inches. In this motor the crankshaft is 
mounted vertically and has but one throw, the 
same as ordinarily used for a single-cylinder 
engine. This crankshaft is stationary—it never 
revolves, but the five cylinders revolve around 
it, as does the front wheel of a motor car on 
the steering spindle. The car is without a radi¬ 
ator, being an air-cooled machine; as the mo¬ 
tor cylinders revolve, a cooling fan is not 
needed. It is without a muffler, each cylinder 
exhausting directly into a box which incloses 
the motor. The motor is directly above the 
transmission set, and as the motor is without 
a flywheel of any sort, it has been necessary for 
the designer to carry the double cone clutch 
within the selective gear set. The drive from 
the revolving cylinders to the gear-set is 
through a bevel gear attached to the base of 
the revolving crank case, and which meshes 
with a bevel gear on one of the transverse 
shafts of the transmission. From the transmis¬ 
sion to the rear axle, a chain drive is employed. 
This car is without a float feed carbureter, but 
uses instead, a pump to maintain a gasoline 
level in a chamber in which a spraying nozzle 
and an air valve complete the carbureter. In¬ 
stead of controlling the motor speed by advanc¬ 
ing or retarding the spark, and opening and 
closing the throttle, it is done by controlling 
the length of time each intake valve is held 
open. This motor has but one cam to open all 


The Automobile Handbook 


13 


of the ten valves. This cam being in two parts, 
it is possible to shift one, thereby varying the 
length of opening given a valve, and allowing 
a part of the mixture drawn into a cylinder to 
escape during a compression stroke, so that the 
explosive pressure can'be varied from 90 lbs. 
to 0, and the power of the motor, and its speed 



Sectional View of Adams Motor 


correspondingly varied. There is no branching 
manifold to convey the mixture to the cylin¬ 
ders, neither is there an exhaust manifold. 

In Fig. 1 is a sectional view of the motor with 
its five cylinders designated respectively 1, 2, 3, 
4 and 5, with five pistons shown in relative po¬ 
sition. The crankshaft A has its one offset B. 
As each cylinder makes, in unison with the 




















14 The Automobile Handbook 

other four, two complete revolutions, it passes 
through the four cycles of operation common 
to any four-cycle engine—inspiration, compres¬ 
sion, explosion, exhaust. No. 4 cylinder is 
shown at the end of the out stroke, and the 
other four at different parts of the stroke; and 
as each in succession occupies the position of 



Cam Diagram—Adams Revolving Cylinder Motor 

No. 4, its piston will be at the end of the out 
stroke. When diametrically opposite to No. 4 
they will be at the inner end of the stroke. 
Thus, as the five cylinders bolted firmly to¬ 
gether to a hublike crankcase revolve, the pis¬ 
tons reciprocate in the cylinders, thus perform¬ 
ing in perfect sequence, the four functions of 
cycling. The valves are located in the cylinder 












The Automobile Handbook 15 

heads and opened by rocker arms with push 
rods paralleling the cylinders on their lower 
sides. One diagram illustrates the single cam 
construction and valve operation. On the lower 
end of the crankshaft is the two-part cam C, 
Cl—Fig. 2. The latter, shown in dotted line, 
is the movable half for controlling the intake 
valve period of opening. Both parts of the 
cam are stationary. On each of the five cylin¬ 
ders is a push rod P, the inner end of which has 
a peculiar foot P2 pivoted on the crankcase 
with the curve portion bearing upon the cam, 
and the short straight arm connected with the 
push rod P. As the cylinder revolves, the 
rounded foot follows the contour of the cam, 
which has been designed so that the four cycles 
follow one another in order as they do in a four¬ 
cycle vertical engine. 

The principles of construction and opera¬ 
tion of the motor just described are similar to 
those found in aeronautical work, such as the 
Gnome and other types of revolving motors. In 
all of these types the crankshaft is stationary 
and the cylinder unit revolves. The power for 
driving is secured by connections on the cylin¬ 
ders. As a general rule, these revolving motors 
are started from rest by revolving the propeller 
blades by hand until the first firing stroke is 
secured. The valve mechanism will differ ac¬ 
cording to the make of motor. In many cases 
the fuel mixture is introduced through hollow 
shafts and castings leading to the cylinders. 


le 


The Automobile Handbook 


Air. Air consists, by weight, of oxygen 77 
parts and nitrogen 23 parts; by volume, of 21 
parts oxygen and 79 parts nitrogen. One pound 
of air at atmospheric pressure, and 70 degrees, 
Fahr., occupies 13.34 cubic feet of space. One 
cubic foot of air weighs 1 1-7 ounces. 


TABLE 1. 

PROPERTIES OF COMPRESSED AIR 


Comp, in 
Atmos 
pheres. 

*Mean 

Pressure. 

Temp, in 
Degrees 
Fah. 

* Gauge 
Pres¬ 
sure. 

‘Absolute 
Pressure. • 

‘Isother¬ 
mal Pres¬ 
sure. 

1 

0 

60 

0 

14.7 


1.63 

7.62 

145 

10 

24.7 

30.39 

2.02 

10.33 

178 

15 

29.7 

39.34 

2.36 

12.62 

207 

20 

34.7 

48.91 

2.70 

14.59 

234 

25 

39.7 

59.05 

3.04 

16.34 

252 

30 

44.7 

69.72 

3.38 

17.92 

281 

35 

49.7 

80.87 

3.72 

19.32 

302 

40 

54.7 

92.49 

4.06 

20.57 

324 

45 

59.7 

104.53 

4.40 

21.69 

339 

50 

64.7 

116.99 

4.74 

22.76 

357 

55 

69.7 

129.84 

5.08 

23.78 

| 375 

60 

74.7 

143.05 

5.42 

24.75 1 

389 

65 

79.7 

156.64 

5.76 

25.67 

405 

70 

84.7 

170.58 

6.10 

26.55 

420 

75 

89.7 

184.83 


*In pounds per square inch. 


Air Properties of Compressed. Table 1 gives 
the Mean pressure, Temperature in degrees 
Fahr., Gauge pressure, Absolute pressure and 
the Isothermal or heat pressure of air under 
compression of from 1 to 6.10 atmospheres. 

As energy in the form of power must be used 
to compress air to any desired pressure, so is 
energy in the form of latent or stored heat 
given up by the air during the operation of 
compression. This heat consequently increases 
the pressure resulting from the compression, 











The Automobile Handbook 


17 


but not directly in proportion to the degree of 
compression in atmospheres. 

This increase of pressure above the Adiabatic 
or calculated pressure is known as the Isother¬ 
mal or heat-pressure. As the values of this 
pressure cannot be calculated by the use of 
ordinary mathematics, but involve the use of 
logarithms, Table 1 gives these values for each 
degree of compression given. 

Many persons who are not familiar with the 
properties of gases, estimate the pressure re¬ 
sulting from the compression to a given number 
of atmospheres, as the number of atmospheres 
multiplied by the atmospheric pressure, which 
at sea level is taken as 14.7 pounds per square 
inch. 

This assumption is erroneous and will often 
lead to grievous mistakes in motor design, 
generally giving too much compression, which 
results in premature ignition, commonly known 
as backfiring. Such methods of calculation 
would be true if the air, after compression, was 
stored in a reservoir and allowed to cool, but 
under no other conditions. 

Air, Relation of to Gasoline. Owing to the 
fact that automobile gasoline is composed of 
various percentages of the several available 
fractions of hydrocarbon distillates, it is not 
possible to fix an exact basis for the relative 
proportions of air to fuel. However, the aver¬ 
age carbureter is capable of altering the ratio 
of air to fuel over broad ranges, and it is not 
necessary to know the exact ratio in order to 


18 


The Automobile Handbook 


attain the best results. But it is necessary to 
approximate an average ratio as nearly as pos¬ 
sible in designing and adjusting carbureters in 
order to allow for these variations up and 
down. 

The mixture becomes explosive when 10,000 
volumes of air dilute one volume of gasoline, 
but the best results follow when the ratio is 
one volume of liquid gasoline to 8,000 volumes 
of air. With one of gasoline to 3,500 of air the 
mixture is non-explosive. 

The proper proportions, from a theoretical 
standpoint, are not always best for practical 
use because a mixture slightly weaker than the 
one found by calculation is more economical in 
the use of gasoline. Such a mixture, of course, 
reduces the power slightly, but the proportion 
of power lost is much less than the proportion 
of gasoline saved. Because of the differences in 
speed of the mixture and the differences in the 
volume being admitted to the engine, it is almost 
impossible to secure a proportion that will be 
uniformly satisfactory over a range of all engine 
speeds. A larger volume of mixture, at a slow 
speed, may be required in ascending a hill at 
ten miles per hour than in traveling on a level 
road at three times this speed. In the latter 
case, the velocity of the mixture will, however, 
be much greater. It is best to secure a mixture 
that will give satisfactory results from the 
standpoint of power at low and medium speeds 
rather than at high. 


The Automobile Handbook 


19 


Air, Relation of in Gasoline Mixture. Gas¬ 
oline is a somewhat uncertain mechanical mix¬ 
ture of several hydrocarbon (fractional) distil¬ 
lates, in which the compound “hexane ’’ is sup¬ 
posed to be the major portion. This compound 
answers to the formula C 6 H 14 , the products of 
combustion of which will be C 0 2 + C O + H 2 0, 
in which C 0 will not be found if the combus¬ 
tion is complete. A final expression of complete 
combustion will be as follows: 

2 C 6 H 14 X 19 0 2 = 12 C 0 2 + 14 H 2 O. 

Taking into account the atomic weight of the 
elements, the volume of air required in the com¬ 
plete combustion of 1 pound of hexane may be 
set down as follows—atomic weight of the ele¬ 


ments involved: 

Carbon (C). 12 

Hydrogen (H). 1 

Oxygen (0).....;. 16 


The molecular weight of C c H 14 = 6 X 12 + 
14X 1 = 86; the required oxygen will weigh 
(molecular) 19 X 16 = 304; the ratio of the 
compound hexane, then, to the combining oxy¬ 
gen will be 

304 

Ratio =-= 3.54, nearly. 

86 

Considering 1 pound of hexane, the weight 
of oxygen required for its complete combustion 
will be equal to the ratio as above given, i.e., 
3.54 pounds, nearly. 

Since the oxygen is taken from the air, it is 






20 The Automobile Handbook 

necessary to consider dry air in the attempt to 
determine as to the weight of the same. This 
air, under a pressure of 1 atmosphere, and at a 
temperature of 60 degrees Fahrenheit contains 
0.23 pounds of oxygen, hence the required air= 

3.54 

-= 15.39, in pounds. 

.23 

Air Resistance, Horsepower Required to 
Overcome. The power required to move a plane 
surface, such as the vertical projection of an 
automobile, against the air, does not become of 
much importance until the car attains a speed 
of 10 to 12 miles per hour, when it becomes an 
important factor. 

The horsepower required to propel an auto¬ 
mobile against the resistance of the air may be 
approximately calculated by the following for¬ 
mula. Let V be the velocity of the car in feet 
per second, and A the projected area of the 
front of the car in square feet—this may be as¬ 
sumed as the height from the frame to the top 
of the body multiplied by the width of the seat 
at the floor line of the car—let H.P. be the 
horsepower required to overcome the air re¬ 
sistance, then 

V 3 X A 

H.P.=- 

240,000 

To simplify the use of the above formula, 
Table 2 gives sneeds in miles per hour corre- 




The Automobile Handbook 


21 


sponding to their respective velocities in feet 
per second and also cubes of velocities in feet 
per second. 


table 2. 

CUBES OF VELOCITIES IN FEET PER SECOND. 


Miles per 
Hour of 
Gar. 

Feet per 
Second. 

Cube of 

V elocity 
in Ft. per 
Second. 


Miles per 
Hour of 
Car. 

Feet per 
Second, 

Cube of 
Velocity 
in Ft. per 
Second, 

10.2 

15 

3,375 


34.0 

50 

125,000 

13.6 

20 

8,000 


40.9 

60 

216,000 

17.2 

25 

15,625 


47.7 

70 

343,000 

20.4 

30 

27,000 


54.4 

80 

512,000 

27.2 

40 

64,000 


61.3 

90 

729,000 


To ascertain approximately the horsepowei 
that will be necessary to drive a car against a 
wind of known velocity, the speed of the cal 
must be added to that of the wind, and the re- 
quired horsepower may be found either by use 
of the formula given or by reference to Table 
3, which gives the horsepower per square foot 
of projected surface required to propel a car 
against the resistance of the air, with varying 
speeds in miles per hour or velocities in feet 
per minute. 

table 3. 

HORSEPOWER REQUIRED PER SQUARE FOOT OF SURFACE, TO MOVE 
A CAR AGAINST AIR RESISTANCE. 


Miles per 
Hour of 
Oar. 

Feet per 
Second. 

Horse¬ 
power per 
Square 
Foot of 
Surface. 

Miles per 
Hour of 
Car. 

Feet per 
Second. 

Horse¬ 
power per 
Square 
Foot of 
Surface. 

10 

14.7 

0.013 

40 


58.7 

0.84 

15 

22.0 

0.44 

50 


73.3 

1.64 

20 

24.6 

0.105 

60 


87.9 

2.83 

25 

36.7 

0.205 

80 


117.3 

6.72 

30 

44.0 

0.354 

100 


146.6 

13.12 


The horsepower given by the formula and 
Table 3 simply refers to the additional power 
























22 The Automobile Handbook 

necessary to overcome air resistance and not to 
the actual power required to propel a car at a 
given speed; this is entirely another matter. 

Alcohol. There are two kinds of alcohol; 
methyl, or wood, alcohol, CH 4 0, and ethyl, or 
grain, alcohol, C 2 H 6 0. The former has been 
found objectionable for use in internal-combus¬ 
tion engines, because it apparently liberates 
acetic acid, which corrodes the cylinders and 
valves. 

As alcohol is a fixed product, and the same 
the world over, it has a great advantage as a 
motive power over gasoline and other petro¬ 
leum products. Denatured alcohol contains 
4,172 heat units per pound as compared to 
18,000 for gasoline, and, as its cost is higher, 
this fuel would not seem practicable from an 
economic standpoint. By mixing the alcohol, 
however, with a high grade of gasoline, its price 
is lowered, and the number of heat units per 
pound greatly increased. Mixtures containing 
50 per cent alcohol have a calorific power of 
11,086 heat units per pound, and as it has been 
found by numerous tests in France that it re¬ 
quires no more of this mixture than of gasoline 
to develop a certain power, its efficiency is con¬ 
siderably greater, reaching a value of 24 per 
cent as compared to 16 for the gasoline motor. 
In some recent experiments in France with a 
motor specially constructed for the use of alco¬ 
hol, the consumption was lowered to 0.124 pound 


The Automobile Handbook 23 

per horse power, using 50 per cent carburetted 
alcohol. 

Grain, or ethyl, alcohol has a specific gravity 
of .795, and may be obtained by distillation 
from corn, wheat, and other grains, potatoes, 
molasses, or anything containing sugar or 
starch. When pure, it absorbs water rapidly 
from the air, more rapidly in fact than it loses 
its own substance, by evaporation; but when 
diluted to the proportion of about 85 per cent, 
alcohol and 15 per cent, water, it evaporates 
practically as if it were a single liquid and not 
a mixture. In France, it is denatured for mo¬ 
tor purposes by the addition of 10 liters of 90° 
wood alcohol, and 500 grams of heavy benzine, 
to 100 liters of 90° ethyl alcohol. In Germany, 
benzol is added to the extent of 15 per cent, for 
denaturing, no wood alcohol being used. In 
the United States the so-called 4 ‘denatured’’ 
alcohol, which is that used in the arts and in¬ 
dustries, is composed of ethyl or grain alcohol, 
to which have been added certain diluents cal¬ 
culated to make it unfit for drinking. The In¬ 
ternal Revenue regulations specify that to 100 
volumes of ethyl alcohol there must be added 
10 volumes of methyl (wood) alcohol and one- 
half of one volume of benzine, or to the same 
quantity of ethyl alcohol must be added 2 vol¬ 
umes of wood alcohol and one-half of one vol¬ 
ume of pyridine bases. 

As compared with gasoline as a fuel for in- 


24 


The Automobile Handbook 


ternal-combustion motors, alcohol exhibits sev¬ 
eral striking peculiarities. 

First, the combustion is much more likely to 
be complete. A mixture of 90° alcohol vapor 
and air will burn completely when the propor¬ 
tion varies from 1 of the vapor with 10 of air 
to 1 of the vapor with 25 of air, thus exhibiting 
a much wider range of proportions for combusti¬ 
bility than is the case'with gasoline. As the 
combustion is complete, the exhaust is practi¬ 
cally odorless, consisting only of water vapor 
and carbon dioxide. 

Second, the inflammability of an alcohol mix¬ 
ture is much lower. This is due partly, no doubt, 
to the presence of water in the alcohol, which 
is vaporized with the alcohol in the engine and 
must be converted into steam at the expense of 
the combustion. 

For these reasons, the compression of an al¬ 
cohol mixture is carried far above that permis¬ 
sible with a gasoline mixture, without danger 
of spontaneous ignition. The rapidity of com¬ 
bustion of alcohol in an engine is considerably 
less than that of a gasoline mixture, and for this 
reason the speed of alcohol engines must be 
somewhat slow. 

The facts that alcohol of sufficient purity for 
use in engines can be produced from the waste 
products of many of the country’s industries, 
and at a nominal cost, and that many thousands 
of acres of land, unfit for the cultivation of 
first-class grain, etc., may be utilized for the 


The Automobile Handbook 


25 


production of vegetable matter rich in the ele¬ 
ments which form alcohol upon fermentation, 
lead to the supposition that within a few years, 
or as soon as there is a sufficient demand for 
alcohol to warrant the erection of special dis¬ 
tilleries, it may be purchased at such a low price 
that it will not only be commercially possible, 
but will in a measure force gasoline and other 
petroleum distillates from the field. 

A carbureter designed to operate with alcohol 
can always be used with gasoline, but the re¬ 
verse conditions are not true, that is, a gasoline 
carbureter will not operate successfully with 
alcohol, except in some rare instances. Alcohol 
evaporates slower than gasoline and its time of 
combustion is much slower, but it maintains its 
mean effective explosion pressure far better 
than gasoline. 

Explosive motors fitted with alcohol carbu¬ 
reters make far less noise than when using gaso¬ 
line as a fuel, due to the slower burning of the 
explosive charge, they also make less smoke 
and smell. 

The jet or spray of a float-feed carbureter will 
have to pass nearly 40 per cent, more liquid 
fuel than when using gasoline, consequently the 
opening in the nozzle must be proportionally 
larger. 

A carbureter using alcohol must be fitted with 
some form of device to heat the alcohol to en¬ 
sure rapid evaporation—this is usually done by 


26 The Automobile Handbook 

surrounding the mixing-chamber with. an ex¬ 
haust-heated jacket. 

The same quantity of alcohol will only take 
a car two-thirds of the distance that gasoline 
will, hence greater storage capacity would be 
needed on a car using alcohol as a fuel. 

An explosive motor designed to use alcohol 
requires a greater degree of compression than a 
motor of the same bore and stroke designed to 
use gasoline, in order to develop the same 
power. 

Alternating Current, Use of. It is not only 

useless but absolutely injurious to attempt to 
charge a storage battery directly from an alter¬ 
nating current circuit. This can only be done 
by means of a rotary converter, which is in 
reality a motor-generator, receiving its power 
from the alternating current and transforming 
it into a direct current which can be used to 
charge the batteries. 

Aluminum. A soft ductile malleable metal, 
of a white color, approaching silver, but with a 
bluish cast. Very non-corrosive. Tenacity 
about one-third that of wrought iron. Specific 
gravity 2.6. Atomic weight 27.1. It is the 
lightest of all the useful metals, with the excep¬ 
tion of magnesium. 

Aluminoid, Composition and Use of. Alu- 

minoid is composed by weight of 60 parts alu¬ 
minum, 30 parts tin and 10 parts zinc. It has a 
tensile strength of about 18,000 pounds and is a 
very suitable material for crank chambers, gear 


The Automobile Handbook 


27 


eases and small brackets, being light, extremely 
ductile and readily machined. 

Aluminum Solder. The following formula is 
for a solder which will work equally well with 
aluminum or aluminoid: Tin, 10 parts—cad¬ 
mium, 10 parts—zinc, 10 parts—lead, 1 part. 
The pieces to be soldered must be thoroughly 
cleansed and then put in a bath of a strong solu¬ 
tion of hyposulphate of soda for about two 
hours before soldering. 

Alloys, Composition of. The proper compo¬ 
sition of alloys of metals for the bearings and 
other parts of an automobile is a very important 
consideration from a constructive standpoint. 
Table 4 gives the composition of various alloys 
of metals and also solders for different uses. 


table 4. 

COMPOSITION OF ALLOYS. 






►>> i 


■d 


Tin. 

Copper 

Zinc. 

! 

a 

< 

Lead. 

3 

6 

m 

A 

Bronze, for Motor bearings. 

13 

110 

1 




Rrnn7P, for AxIp hpnrings. 

25 

160 

5 




Brass, for light work, other than 
hearings . 

2 

1 




Bronze flanges, to stand brazing... 
Gonninp Rflhhift mptnl. 

io 

32 

1 

1 

i 

1 

... 

Rrnri7P for bushings . 

16 

130 

i 




Metal to expand in cooling, for 
patterns . 


2 

9 

1 

Genuine bronze . 

Soldpr for tin .] 

2 

1 

90 

5 


2 

2 


Spelter, hard . 


1 

1 




Spelter, soft . 

i 

4 

3 



• . • 

It should be understood that 

no 

definite rule 


can be given for the proportioning of any one 
alloy for the reason that a slight change in the 





























28 


The Automobile Handbook 


amount of one or more of the elements may suit 
the metal exactly for some proposed use, while a 
porportion only slightly different might give un¬ 
satisfactory results. 

Ammeter, Construction of. Ammeters for 
automobile use are constructed on the principle 



Fig. 3 


of the D’Arsonval galvanometer with a perma¬ 
nent magnetic field. The special feature is a 
small oscillating coil mounted on cone-point 
bearings surrounding a stationary armature 
which is centrally located between the pole- 
pieces of a permanent magnet, with a pointer 
or index-finger which indicates the electrical 
variations on a graduated scale. 































The Automobile Handbook 29 

The construction of an' ammeter is fully 
show in the two views in Figure 3. The per¬ 
manent magnets used in its construction are of 
a special quality of hardened steel, made only 
for this purpose and possessed of great mag¬ 
netic permeability. The pole-pieces, which are 
of soft steel and well annealed, are attached to 
the inside of the lower part of the magnet legs, 
the joints between the pole pieces and the mag¬ 



net legs are usually ground to insure the full 
efficiency of the magnetic circuit. The soft iron 
core of the coil is for the purpose of rendering 
uniform the magnetic field in which the coil 
must oscillate. A coil of insulated wire is 
wound upon the stationary armature at right 
angles to its axis, in the same manner that 
thread is wound upon a spool, and is short-cir¬ 
cuited on itself, that is to say, the ends of the 
wire forming the coil are connected together. 
This coil of wire is for the purpose of choking 



















30 The Automobile Handbook 

the magnetism induced in the stationary arma¬ 
ture by the oscillating coil, as it generates what 
are known as eddy currents within itself, thus 
making the instrument periodic, or dead-beat, 
in its indications. Around the armature core 
and outside the short-circuited coil of wire is 
wound the active or oscillating coil and at right 
angles to the direction of the winding of the 
first coil. The oscillating coil consists of a num¬ 
ber of turns of fine insulated copper wire, to 
which the current is conveyed through the me¬ 
dium of the controlling springs at each end of 
the, spindle, which is in two parts and con¬ 
nected together by a suitable sleeve of insulat¬ 
ing material, as shown. 

The pointer or index-finger is made with a 
boss or hub to go over the end of the spindle of 
the active coil and also has an extension with a 
small counterweight or balance, so that the 
pointer may be accurately adjusted. 

The only difference in the construction of a 
voltmeter and an ammeter is that in the former 
the active or oscillating coil is in series with a 
high resistance, while in the latter it is con¬ 
nected across the terminals of a shunt-block. 
The voltmeter is in reality an ammeter, the re¬ 
sistance serving to keep the amperage in step 
with the voltage. 

Reference to the three views, marked re* 
spectively A, B and C in Figure 4, will show 
clearly the principle of the operation of an 
ammetev or voltmeter, and the reason that they 


The Automobile Handbook 


31 


record the current strength or pressure of an 
electric current accurately. 

Ammeters are of two kinds, the double-beat 
type, as shown in Figure 3, which indicates the 
current strength or number of amperes flowing 
in the electric circuit, without any regard to 
the polarity of the terminals of the circuit, by 
the pointer or index-finger moving either to the 
right or to the left of the zero position. The 



single-beat type of ammeter only records in 
one direction, by the pointer moving from the 
left to the right of the graduated scale of the 
instrument, consequently the polarity of the 
terminals of this type of ammeter are marked 
on its outer casing and the polarity of the ter¬ 
minals of the electric circuit must consequently 
be determined before connecting them with the 
ammeter. 















32 


The Automobile Handbook 


Ampere. The unit of electric current flow. 
An ampere is that volume of current which 
would pass through a circuit that offered a re¬ 
sistance of one ohm, under an electromotive 
force of one volt. 

Ampere-hour, Definition of. The term am¬ 
pere-hour is used to denote the capacity of a 
storage or a closed-circuit primary battery for 
current. A storage battery that will keep a 2 
ampere lamp burning for 8 hours is said to 
have a 16 ampere-hour capacity. In a similar 
manner an 80 ampere-hour battery would ope¬ 
rate the same lamp 40 hours. The voltage of a 
battery does not enter into the calculation of 
its ampere-hour capacity. 

Anti-Freezing Mixtures. If a solution of al¬ 
cohol and water is used, the best results will be 
obtained by having it just strong enough to 
stand the lowest temperature to which it is 
likely to be subjected in the climate where it 
is to be used. 

The reason for this is that the alcohol evapo¬ 
rates out from the solution, and the stronger the 
solution, the more there is to evaporate, the 
easier it evaporates, and the greater the influ¬ 
ence of this evaporation upon the solution left. 

The diagram shown on page 33 indicates the 
freezing points of various solutions of dena¬ 
tured alcohol, also of wood alcohol. From this 
diagram a solution may be selected which will 
stand any temperature from 50° below zero to 
40° above. 


The Automobile Handbook 


33 


Other solutions may be made with calcium 
chloride (common salt), also the salts known as 
potassium carbonate. These with water form a 
solution that will stand zero temperatures, but 
are not available where lower temperatures are 
common. 



Non-Freezing Mixtures for Radiators. In 
cold weather, the circulating water, the oil, 
and the carbureter require special attention. 
If the car is to be run regularly during 

























34 


The Automobile Handbook 


the winter, it is advisable to use a non- 
freezing mixture in the water-jacket. If the 
car is not to be used regularly, it may not 
be necessary to employ such a mixture, but in 
that case great care is necessary to prevent the 
water from freezing unexpectedly. If the car 
is kept in a barn, the water should be drawn 
off completely after the car has been used, and 
the drainage cock should be so located and the 
piping so arranged that there are no water 
pockets in which the water may freeze and ob¬ 
struct the circulation. If the water freezes in 
the pump, the latter is likely to be broken when 
the car is started the next morning. If water 
freezes in the water-jackets, it will burst the 
jackets unless they are made of copper. When 
the car is left standing for an hour or so, cloths 


Proportions of Glycerine, Alcohol and 
Water. 


Freezing 

Point 

Glycerine and 

Alcohol (equal parts) 

Water 

28° above 

15% 

85% 

15° above 

20% 

80% 

10° above 

24% 

76% 

5° above 

28% 

72% 

Zero 

30% 

70% 

5° below 

33% 

67% 

10* below 

36% 

64% 



The Automobile Handbook 


35 


or lap robes may be thrown over the radiator 
to cheek the cooling; this is cheaper and safer 
than leaving the motor running. 

The two substances most used to prevent 
freezing are glycerine and calcium chloride. A 
30-per-cent solution of glycerine in water 
freezes at 21° F.; and a solution of one part of 
glycerine to two parts of water is safe from 
freezing at 10° or 15° F.; 40-per-cent solution 
freezes at zero. A small amount of slaked lime 
should be added to neutralize any acidity in the 
solution. Glycerine has the objection that it 
destroys rubber, and the solution fouls rather 
quickly. 

A cheaper mixture, and one preferable where 
the temperatures encountered are likely to be 
below 15° or 20° F., is a solution of calcium 
chloride. This must be carefully distinguished 
from chloride of lime (bleaching powder), 
which is injurious to metal surfaces. Calcium 
chloride costs about 8 cents a pound in bulk, 
and does not materially affect metals except 
zinc. A saturated solution is first made by add¬ 
ing about 15 pounds of the chloride to 1 gallon 
of water, making a total of about 2 gallons. 
Some undissolved crystals should remain at 
the bottom as evidence that the solution is sat¬ 
urated. To this solution is added from 2 to 3 
gallons of water, the former making what is 
called a 50-per-cent, solution. A little lime is 
added to neutralize acidity. A 50-per-cent so¬ 
lution freezes at —15 Q F, 


36 The Automobile Handbook 

Whether glycerine or calcium chloride is 
used, loss by evaporation should be made up by 
adding pure water, and loss through leakage by 
adding fresh solution. In using the chloride, 
it is important to prevent the solution from ap¬ 
proaching the point of saturation, as the chlo¬ 
ride will then crystallize out and clog the radi¬ 
ator, besides boiling, and failing to cool the 
motor. A 50-per-cent, solution has a specific 
gravity of 1.21, and should be tested occasion¬ 
ally by means of a storage-battery hydrometer. 
Equally important is it to prevent the water 
from approaching the boiling point, whatever 
the density, as boiling liberates free hydrochlo¬ 
ric acid, which at once attacks the metal of the 
radiator and cylinders. 

A solution of two parts of glycerine, one part 
of water, and one part of wood alcohol has been 
recommended, which is said to withstand about 
zero temperature. 

Certain mineral oils used for the lubrication 
of refrigerating machinery are recommended 
for cooling, because they remain liquid at very 
low temperatures. They are not particularly 
good heat conductors, however, and will not 
keep the motor as cool as the water solution. 
If the oil is used, it must be cleaned from the 
radiator by the use of kerosene and oil soap, 
before water can again be used effectively. 

As regards lubrication, the principal danger 
is that the oil will thicken from the cold so that 
it will refuse to feed. This is avoided by using 


The Automobile Handbook 


37 


cold test oil, which remains liquid at lower tem¬ 
peratures than ordinary oil, or by adding to the 
ordinary oil some kerosene or gasoline, and in¬ 
creasing the feed. If the oil tank is located 
close to the engine, it will remain liquid, even in 
quite cold weather. But unless the car has been 
kept in a warm place over night, the bearings are 
liable to run dry before the car has warmed up. 

Cooling Solutions—For Winter. Radiators 
are costly, delicate and composite in construc¬ 
tion, the latter due to the plurality of metals in 
their make-up, hence electrolytic action takes 
place, due to the difference of potential nat¬ 
ural to the different metals immersed in a saline 
bath. Therefore great care should be exer¬ 
cised in the preparation of anti-freezing solu¬ 
tions made up of calcium chloride (common 
salt and water). Any approach to the satura¬ 
tion limit is attended with danger of precipita¬ 
tion. The saturated solution is ascertained at 
60 degrees F., and increasing the temperature 
increases the capacity of the water to hold the 
salts in suspension. 

On the other hand, the Ohmic resistance of 
a solution is lowest at about half saturation. 
To sum up, it is experience that counts, and 
it is still a question as to the extent to which 
saline solutions can be used with safety. Of 
course there is no solution as good as water 
alone, but unfortunately water will expand 
when it freezes, and it will freeze on small prov¬ 
ocation in a radiator. Oil as a cooling medium 


38 The Automobile Handbook 

has points in its favor which some authorities 
claim render it more efficient than water, as 
for instance it has a higher boiling point, about 
double that of water, and as a result the oil 
will not waste away except by leakage. The 
heat exchange occurs at a higher temperature, 
thereby increasing the efficiency of the motor. 
Then also the area of radiating surface may be 
smaller, with a conesquent decrease in weight, 
while the work of the fan is rendered of less 
importance. A light, thin, pure mineral oil is 
the most reliable. Animal, and vegetable oils 
are more apt to become rancid, the acid in them 
also attacks the metal of the radiator. 

Armatures, Dynamo. The armature, or re¬ 
volving member of lighting dynamos, is com¬ 
posed of a core made from wrought iron or mild 
steel. It is customary to make this core by as¬ 
sembling a sufficient number of thin plates 
made in the form *of the cross section of the 
core, these plates being covered with an insulate 
ing composition and then fastened together on 
the shaft. This construction prevents the for¬ 
mation of harmful “eddy currents” within the 
metal. 

The assembled core has a number of slots run¬ 
ning lengthwise of its body and in these slots 
are placed the armature coils or winding of in¬ 
sulated wire. The coils are then connected to 
a commutator mounted on one end of the shaft 
in such a way that the current generated may 
be collected by the brushes. 


The Automobile Handbook 


39 


Armatures, Slotted and Shuttle Types of. 

An armature is the rotating part of a dynamo 
or electric motor which generates electricity or 
develops power. 



The armature shown at right of Fig. 6 is 
known as the Siemen’s H or shuttle type and is 
the simplest form of wire-wound armature 
known. The current given by this form of 
armature is of the alternating type and is con¬ 
verted into a direct-current, when desired, by 
means of a two-part commutator on the arma¬ 
ture shaft. 

The slotted type of armature shown at the 
left -of Fig. 6 has a more intricate sys¬ 
tem of winding than the shuttle type just de¬ 
scribed. It has, however, a far greater elec¬ 
trical efficiency and gives off a steadier current 
than the shuttle type. It is the form most gen¬ 
erally used for automobile and street railway 
motors. Like the shuttle type of armature, the 
current generated by the slotted type of arma¬ 
ture is alternating, and is converted into a di¬ 
rect current by means of a commutator of very 
complicated form. 




40 


The Automobile Handbook 


Assembling a Car. In assembling the car the 
engine had best be put together first. When 
putting the pistons in their respective cylinders 
see that the splits or joints in the piston rings 
are not in line, but are spaced evenly around 
the piston. See that all parts are thoroughly 
clean and that no grit, or stray strands of waste 
happen to be caught on any projection. All 
nuts and bolts should be screwed tight and the 
jaws of the wrench should be properly adjusted 
to them, that the corners of the nuts and cap 
screws may not be rounded off. Insert the cot¬ 
ter pin after each nut has been screwed home. 
In joints where packing is required the old 
packing may be used if it is in good shape. 
Joint faces should, of course, be perfectly clean. 
A stout grade of manila wrapping paper soaked 
in linseed oil will make an excellent packing for 
crankcase and other joints having a good con¬ 
tact surface. 

While the engine is being reassembled it will 
be found advantageous to check up the valve 
timing. To do this, turn the fly-wheel until 
the inlet valve plunger of No. 1 cylinder just 
touches the lower end of its valve stem. At this 
point the line on the fly-wheel indicating “Inlet 
No. 1 Open” should coincide with the pointer 
on the engine base. If the contact between the 
valve stem and the plunger is made before the 
mark on the fly-wheel lines up with the pointer, 
the valve opens too early. In most cars the 
adjustments may be made by the screw cap and 


The Automobile Handbook 


41 


lock-nut on the plunger. As the valve stems are 
lowered by repeated grindings of the valves, 
the plungers require adjustment occasionally 
to compensate for this movement. Insert a 
piece of paper between plunger and valve stem, 
and by lightly pulling on the paper the time of 
contact and the moment of release may be de¬ 
termined to a nicety. When the paper is held 
tightly, a good contact is assured, and the mo¬ 
ment the paper becomes loose and can be moved 
about, the contact is broken. In many cars the 
reference or index mark on the engine bed is 
omitted; in this case the markings on the fly¬ 
wheel must be brought directly to the top. The 
other inlets and the exhaust valves should then 
be similarly checked up and adjusted. 

Most cars base the valve setting on a 1-32 
inch clearance space between valve stem and 
plunger rod when the valve is closed. This 
may be taken as the minimum amount, and 
should not be increased. A larger amount of 
clearance will cause the exhaust valve to open 
too late, and, the exploded gases not being en¬ 
tirely expelled, the power of the motor will be 
impaired. This clearance is necessary to allow 
for the expansion of the valve stem when it be¬ 
comes heated. 

Too much stress cannot be laid on the neces¬ 
sity of going about the work in an orderly and 
methodical manner. A mechanic who leaves 
parts lying about carelessly will rarely be found 
a good one, and certainly he is not. a proper 


42 


The Automobile Handbook 


model for the amateur to copy. With the proper 
circumspection, then, and with a little “horse 
sense” in applying the directions to his par¬ 
ticular make of car, the amateur owner should 
have no difficulty in making a good job of over¬ 
hauling, thus bettering the condition of his ma¬ 
chine and at the same time acquiring a valua¬ 
ble stock of knowledge for the future. 

Automobile Driving. When on the open 

road, away from cities or towns, the fol¬ 
lowing rules should be borne in mind. (1) 
Drive with moderate speed on the level, slow 
speed down hill, and wide open throttle for 
hill climbing, or getting up speed only. (2) 
The condition of the road should be noticed, 
the presence of mud or dust thereon furnishing 
sufficient reason for slowing down somewhat 
for the sake of other road users. (3) The or¬ 
dinary rules of the road regarding the negotia¬ 
tion of turns, and crossings, also the overtak¬ 
ing or passing of other vehicles should be ad¬ 
hered to, even though a lower rate of speed is 
involved thereby. (4) A sharp lookout should 
always be kept for traffic of all kinds, as well 
as on approaching schools, churches, or public 
buildings, and also for road signs indicating 
danger, caution, etc. (5) When on the road 
the autoist should show courtesy to other road 
users. Courtesy in autoists is much appreci¬ 
ated, and goes a long way toward removing 
the prejudice which exists in many places 
against automobiles. 


The Automobile Handbooh 


43 


Gear—Changing. In changing gears the au- 
toist should endeavor to have the motor and 
car moving at nearly corresponding rates of 
speed before the clutch is engaged. With the 
planetary type of gear, changing is simple, and 
drivers usually guess at the proper period at 
which to make the change, any mistake in esti¬ 
mating the rates of the car and motor being of 
little consequence, as the bands will slip instead 
of transmitting the shock to the gear. A simi¬ 
lar action occurs in the case of individual 
clutch or friction gears, but with the sliding 
type severe strains and shocks have to be taken 
up by the clutch, and are usually transmitted in 
j)art to the gear if the clutch is not slipped. 
What applies to the sliding type in general ap¬ 
plies to the other types as well. 

In changing from a lower to a higher gear it 
will be necessary to speed up the motor by 
means of the throttle or accelerator in order to 
store enough energy in the flywheel to furnish 
the work needed to accelerate the car to its 
new speed. As the speed of the car increases 
the higher gear should be engaged, the autoist 
not being in too great a hurry to make the 
change. The movement of the change gear le¬ 
ver should be made quickly in order that the 
car does not lose way. When changing from a 
higher to a lower gear the change should be 
made as quickly as possible before the car has 
time to slow down. When climbing a steep hill 
it should be ascended as far as possible on the 


44 


The Automobile Handbooh 


high gear by proper use of the throttle and 
spark, and the change down to the lower gear 
made as soon as the motor begins to labor or is 
in danger of stopping. The presence of an 
unusual number of passengers in the car will 
affect its ability to negotiate grades which ordi¬ 
narily are taken on the high gear, and the auto- 
ist should remember this and not attempt to 
force the car to travel on that gear with the in¬ 
creased load, but resort to a lower gear. 

Reversing—Backing Up. Among other things 
connected with driving which is apt to be neg¬ 
lected, is reversing, or driving a car backward. 
Usually a car is never reversed for more than 
a few yards at a time and the maneuvering in¬ 
volved requires no great skill. Steering a car 
when running backwards is diametrically op¬ 
posite to that when running forward. A turn 
of the wheel to the left steers the car in the 
opposite direction to the right, and vice versa. 
The usual mistake made in reversing is in turn¬ 
ing the steering wheel too far, and describing 
zigzags in the road as a result. The autoist 
should remember that the reverse gear of a 
sliding change gear should never be engaged 
until the car has been brought to a full stop. __ 

Brakes, Proper Use of. Next to the motive 
power in importance come the brakes. There 
are a number of points regarding brakes that 
every autoist should know and remember. First 
-and most important is the fact that brakes vary 
in their effectiveness, and that freedom from dis- 



The Automobile Handbook 


45 


aster depends upon the brakes being kept in 
good condition and properly adjusted. Second, 
while a brake may be perfectly satisfactory for 
slowing down, it by no means follows that it will 
bring a car to a stop as it should, nor hold the 
car from going backward. Third, brakes 
should be tested frequently with the car in 
motion, the pedal or hand lever being applied 
until the car slows down, or stops. The distance 
covered in making this test should be noted, 
and a greater distance allowed in making stops 
on the road. 

In applying brakes, the application should be 
gradual, reducing the speed of the car as quickly 
as possible without locking the wheels. As long 
as the tires retain their grip on the road, the 
powerful retarding action of the brake contin¬ 
ues, but when the wheels are locked the brakes 
have little or no effect, and the car will either 
slide along, or skid, in either case being be¬ 
yond the control of the driver. Should the 
wheels become locked while descending a hill, 
the brakes should be released until the wheels 
are again revolving, and then reapplied gradu¬ 
ally, until they act satisfactorily. 

Brakes should be examined at regular in¬ 
tervals in order to ascertain if the lining is in 
good condition. If worn, the old lining should 
be replaced with new. If the brakes are of the 
internal-expanding type, the shoes may have 
become worn, in which case they should be re¬ 
newed. Toggle joints and adjusting nuts 


46 


The Automobile Handboolc 


should be inspected, and any looseness taken up. 
Brakes should be adjusted on the road, as any 
improper adjustment of the equalizer bar will 
have a strong tendency to make the car skid. 
Both brakes should be adjusted alike, that the 
braking force applied by the equalizer may be 
transmitted to the wheels equally. 

Side Slip, or Skidding. If the rate of rota¬ 
tion of a wheel is greater than the rate of ad¬ 
vance over the road, the wheel loses adhesion 
and thereafter it is just as easy for it to move 
in one direction as in another. 

The wheel can now slip sideways as easily 
as it can slip forwards, particularly when it has 
the rounded section slightly flattened, which is 
the case with pneumatic tires. When traveling 
straight ahead, and with the motor out of gear, 
skidding does not usually occur. A slight turn 
given to the steering wheel checks the speed 
and introduces a side pressure on both front 
and rear wheels, due to the machine tending to 
continue its path in a straight line. Generally 
this side pressure will not cause skidding. If, 
however, the motor be suddenly thrown in gear, 
or the brakes suddenly applied, or, what 
amounts to the same, a large turn is given the 
steering wheel, the wheels find themselves 
either rotating more than in proportion to their 
advance, or advancing more than in proportion 
to their rotation. This immediately causes a loss 
of adhesion, which, once established, causes the 
car to skid or side-slip. 


The Automobile Handbook 


47 


Spark—Regulation of. Upon the proper use 
of the sparking device depends the economy of 
the motor, and in many cases the safety of the 
driver. On some cars the sparking point on the 
magneto is fixed, and the autoist controls the 
car by the throttle only. There are a number 
of cars in use which employ the battery in con¬ 
nection with separate coils or a single spark sys¬ 
tem, or a magneto on which the spark can be 
regulated by the driver. When starting, the 
spark should be retarded in the case of battery 
ignition, to prevent backfiring, and slightly ad¬ 
vanced to a certain point, depending on the 
motor and magneto, in the case of magneto igni¬ 
tion. When it is desired to slow the motor 
down below the point obtained by throttling 
only, the spark is likewise retarded. In ordi¬ 
nary running, a position of the spark lever can 
be found which will give fair average results 
through a considerable range of speed without 
changing its position, and this position varies 
with each motor, and can be found by experi¬ 
ence. When a higher rate of speed is desired, 
the throttle is opened and the spark advanced 
gradually. If a grade is to be negotiated it 
should be “rushed’’ if possible, the throttle be¬ 
ing opened full and the spark well advanced 
until the motor begins to slow down and 
i ‘ knock/ ’ when the spark should be retarded to 
correct this. The autoist should always keep 
the spark as far advanced as possible, without 
causing the motor to knock. 


48 


The Automobile Handbook 


When to Retard the Ignition. Always r&- 
retard the ignition before starting the motor, 
and take great care that the ignition is retarded 
and not by mistake advanced. Some cars are 
fitted with a device which prevents the starting 
crank being turned unless the spark is retarded. 
If it is not clear as to which way to move the 
ignition lever to retard the ignition, move the 
commutator in the same direction as the cam¬ 
shaft rotates. 

As soon as the motor slows a little when go¬ 
ing uphill, retarding the spark enables more 
power to be obtained from the motor at the 
slow speed, that is to say, if the spark is not 
retarded the motor will go slower than if it is 
retarded. Do not retard the lever to the utmost 
under these conditions; on the contrary, retard 
the lever to such a point that the knocking (due 
to the wrong position) ceases. 

Retarding the spark causes the maximum 
pressure of the explosion to occur at the best 
part of the stroke, or, rather, the mean pressure 
of the explosion stroke will be*lower if the best 
point of ignition by retarding is not found. This 
is a matter of some skill and practice. 

To slow the motor, cut off as much mixture 
as the throttle allows, then slow the motor still 
further by retarding the spark, but on no ac¬ 
count retard the spark when the throttle is full 
open (for the purpose of slowing the motor), 
as the motor will merely discharge a quantity 
of flame at a white heat over the stem of the 


The Automobile Handbook 


49 


exhaust valve, burning it, softening it, and 
making it scale. 

When to Advance the Ignition. With too 
early ignition the pressure upon the piston be¬ 
comes excessive and without any adequate re¬ 
turn of useful work or energy. If the ignition 
be retarded too much, the maximum explosive 
pressure occurs too late during the working 
or power stroke of the piston, and the combus¬ 
tion of the gases is not complete when the ex¬ 
haust-valve opens. Greater motor speed re¬ 
quires an early ignition of the charge, but 
greater power calls for late or retarded igni¬ 
tion. 

The reason for advancing the spark when 
fast running is required, is that the explosion 
or ignition of the charge is not instantaneous 
as may be supposed, but requires a brief inter¬ 
val of time for its completion. 

It may be well to explain without entering 
into theoretical details, that when a motor is 
running at normal speed, the ignition-device is 
so set that ignition takes place before the pis¬ 
ton reaches the end of its stroke. The later 
the ignition takes place the slower the speed 
of the motor and consequently the less power it 
will develop. If, however, in starting the mo¬ 
tor the ignition-device were set to operate be¬ 
fore the piston reached the end of its stroke, 
backfiring would occur, resulting in a reversal 
of the operation of the motor and possibly in 
injury to the operator. 


50 


The Automobile Handbooh 


Car Inspection. Most autoists are content to 
make all their inspection of the car and its mech¬ 
anism from above, and rarely give more than a 
casual glance below the frame except when 
trouble occurs. On cars fitted with pressure-feed 
on the gasoline, the piping should be frequently 
inspected, on account of the danger from fuel 
leakage. Such inspections should be made 
when the motor is stopped, and the pressure still 
turned on. The tank should be gone over for 
leaks arising through the opening of its seams 
from vibration, or the loosening of the union 
connecting the fuel lead with the tank. The 
lead and its connection to the carbureter should 
also be examined for leaks and abrasions due to 
rubbing against other parts of the mechanism. 
If any such are found they should be immedi- 
diately repaired. Twine, tire tape, or rubber 
bands will act satisfactorily as fenders to pre¬ 
vent further mischief. Unions which cannot be 
made tight by screwing up should be taken 
apart and the male connections coated with 
soap or red lead, which will render them tight 
for a considerable time. 

After going over the fuel system, the brake 
rods and steering connections should be exam¬ 
ined for loose joints and broken oil and grease 
cups. Grease boots on the drive-shaft joints 
should be seen to be sound, and filled with 
grease. A cleaning out of the dirt from the in¬ 
terior of the mud-pan will often reveal lost cot¬ 
ter pins or nuts, and tend to a more agreeable 
handling of the draincocks, carbureter and fil- 


The Automobile Handbook 


51 


ter. This time will be well spent when the 
chances of fire or accidents arising from faulty 
steering or brake connections are taken into 
account. 

Dont’s. In the first place don’t forget to as¬ 
certain the fact that the ignition mechanism is 
retarded before cranking the motor. Many a 
sprained wrist and a few cases, of broken 
heads or arms have been caused by the neglect 
of this simple precaution. It is a good plan to 
have the ignition-control spring so actuated that 
in its normal position it is always retarded. 

Don’t use the electric starting motor to pro¬ 
pel the car. It ruins the battery. 

Don’t use a match or a small torch to inspect 
the carburetor. It sometimes leads to unex¬ 
pected results. 

Don’t forget to fill the gasoline tank before 
starting. 

Don’t smoke while filling the gasoline tank. 

Don’t take out all the spark plugs when 
there is nothing the matter, except that there 
is no gasoline in the tank. 

Don’t forget to always have an extra spark 
plug on the car. 

Don’t allow the motor to race or run fast 
when out of gear. If the car is to be stopped 
for a few minutes, without stopping the motor, 
retard the ignition and also throttle the charge, 
so that the motor will run as slowly as possible. 

Don’t fill the gasoline tank too full, leave an 


52 The Automobile Handbook 

air space at the top or the gasoline will not flow 
readily. 

Don’t have any open hole in the gasoline 
tank. When the car is washed water may rnn 
in this hole, mix with the gasoline and cause 
trouble. 

Don’t put grease in the crank case of the 
motor, it will clog up the oil holes and prevent 
the oil from circulating. 

Don’t fill the gasoline tank by lamp or candle 
light, something unexpected may happen. 

Don’t keep on running when an unusual noise 
is heard about tfie car, stop and find out what 
it is. 

Don’t start or stop too suddenly, something 
may break. 

Don’t pour gasoline over the hands and then 
rub them together. That rubs the dirt into the 
skin. The proper way to do is to saturate a 
towel with gasoline and then wipe the dirt off. 

Don’t forget to examine the steering gear 
frequently. 

Don’t fail to examine the pipe between the 
carbureter and the admission-valve occasionally. 
The pipe connections sometimes get loose and 
allow air to enter and weaken the mixture. 

Don’t forget to see that there is plenty of 
water and gasoline in the tanks. 

Don’t fail to clean the motor and all the 
wearing parts of the car occasionally. 

Don’t forget to oil every part of the motor 


The Automobile Handbook 


53 


where there is any friction, except the valve 
stems. 

Don’t forget to put distilled water in the bat¬ 
tery every ten to fifteen days. 

Automobile Tools. In Fig. 7 three types 
of valve lifters are shown. B and C are of the 
same principle, and quite efficient in almost any 
case; but A, when properly operated, and on 
its respective motor, is more quickly applied, 



and consequently a time saver. D is a valve¬ 
seating tool, supplied as special equipment by 
one of the large motor car manufacturers. 

In Fig. 8 are shown a couple of spanner 
wrenches and one or two other tools that are 
quite uncommon but quite necessary in the work 
to which they are adapted. A is made from a 
piece of steel tubing and used on packing 
glands—the tube to slip over the shaft—and the 
small lugs at the end engage corresponding 











54 


The Automobile Handbook 


recesses in a packing nnt. B is representative 
of a valve-grinder, designed especially for the 
valves in certain motors. The spanner C is re¬ 
quired to conveniently remove certain types of 
cylinder plugs; while D, which approaches the 
conventional, is used in adjusting bearings of 
a particular type. 

There is probably a greater variety of wheel 
and gear pullers now in service than of any 



other special tool. In Fig. 9, A looks very 
much like the standard adjustable wheel and 
gear puller for sale in all supply houses; and 
it practically is the same except that the hooks 
are larger and twisted in opposite directions 
and at right angles to the beam. It is found 
useful in removing road and flywheels and the 
like. B is a non-adjustable tool made especially 
for removing flywheels. C and P are road wheel 
pullers, and are included in the regular equip- 





The Automobile Handbook 55 

ment of tools supplied with the cars of two 
prominent manufacturers. C is part of the 
Rambler tool equipment and is used in connec¬ 
tion with their spare wheel; and P represents 
the type of wheel puller supplied by the Pierce- 
Arrow. E is a gear-puller designed to remove 
the half-time-gears of an Oldsmobile, the two 



side-screws being intended to fit into threaded 
holes in the web of the gears. 

When the Jack is Missing. Should the jack 
be missing or broken, an efficient substitute can 
be rigged from a large stone or a number of 
bricks piled one on another until the height is 
sufficient to lift the wheel from the ground. 


















56 


The Automobile Handbook 


Having gotten the stone or piled the bricks one 
of the floor-boards can be utilized as an inclined 
plane and the car backed up until the axle rests 
on the top of the pile. When the work has been 
performed, the axle will have to be pushed off 
the pile, but as the drop is inconsiderable no 
harm can come to the tire. Where stake-and- 



Fig. 10 . 

Removing Dent in Gasoline Tank 


rider fences abound, one of the rider timbers 
can be utilized as a lever, with a stone as a ful¬ 
crum to raise the axle, supporting the latter 
with another stone during the repair, and gently 
easing down the axle when ready to proceed. 

Removing Dents. An easy method of remov¬ 
ing dents consists of soldering a piece of wire 
to the bottom of the dent, then pulling the de- 












The Automobile Handbook 


57 

pressed portion out to its proper position. When 
the dent happens to be in an oil, or gasoline 
tank, or a radiator, an old valve can be most 
effectively used in place of the wire, as shown 
in Fig. 10 The top surface of the valve is hied 
smooth and bright, then cleaned with soldering 
acid and tinned with solder. A flat surface of 
the same area, and as near the bottom of the 
dent as possible, is treated in the same 'manner, 
and the valve sweated on. This sweating on is 
done by placing the prepared portion of the 
valve against the tinned surface of the dent, 
and then applying heat with a torch till a fu¬ 
sion of the solder takes place. The heat should 
then be removed and the solder allowed to set. 
When cool, it will be found that with the valve 
stem as a handle and lever, and probably a few 
light taps with a hammer around the edge of 
the dent, the deformed part can be most easily 
straightened out. 

Tools Necessary. The following tools should 
be in the car when on the road: 

Monkey wrench, 9 inch. 

Machinist’s screwdriver. 

Ball pene hammer, one pound. 

Combination pliers, 8 inch. 

Set of double end, or “S” wrenches. 

Flat file, mill cut. 

Three cornered file. 

Round file, six inch. 

Center punch. 

Prick punch. 


58 The Automobile Handbook 

Drift punch, flat ended. 

Offset, or 4 ‘ bent-end ’ ’ screwdriver. 

Cold chisel, three-quarter inch. 

Spark plug wrench. 

Small wire cutting pliers. 

Emery cloth. 

Cotter pin puller. 

"Wire brush for spark plugs. 

Break Downs, and Their Remedies. 

Chain Broken. In case a chain should break, 
and there are no spare links available, the car 
may be driven by the other chain, provided the 
idle sprocket is secured so that it cannot re¬ 
volve. An easy way to do this is as follows: 
Pass one end of the chain around the sprocket, 
secure the end link to the chain with wire, and 
attach the other end of the chain to some part 
of the car, as a running board bracket. 

On shaft driven cars the universal joint pins 
sometimes work loose, and drop out. In such 
cases a temporary pin can be made from a bunch 
of wire, or by a "mail chisel held in place by 
wires, or twine. 

Circulating Pump Leakage. Leakage of 
the water circulating pump occurs usually 
where the cover joins the pump body by means 
of a ground joii^t. A gasket of stiff paper 
dipped in lubricating oil inserted between the 
cover and the body will remedy this, the gasket 
being easily formed with the pocket knife. As¬ 
bestos cord is better than paper when treated 
with vaseline and graphite, but few autoists 


The Automobile Handbook 


59 


carry it. For leakage around the pump spindle 
the cord can be used, pushing it in with a piece 
of strip brass or other soft metal so as to avoid 
scratching the shaft. If no asbestos cord is at 
hand one of the strands of a piece of hemp rope 
treated with tallow will also answer. 

Cranking with Safety. The principle in¬ 
volved in safely cranking an engine is, to get 
the explosion at the moment the crank is pull¬ 
ing on the fingers, so that if the kick comes the 
force will simply pull the handle out of the 
grasp, instead of being expended against the 
body weight and applied force. Do not attempt 
to turn the crank all the way around; adjust it 
to start against the compression, then give a 
quick pull upward. 

Differential Casing. In cases of emergency 
where oil or grease cannot be obtained for fill¬ 
ing the differential casing, beeswax may be 
used as a substitute. 

Dry Cells for Ignition. Dry cells will give 
very satisfactory ignition for a four cylinder 
motor by using four sets of four cells each, con¬ 
nected in series multiple so as to get a voltage 
of only six volts. By having the vibration re¬ 
spond quickly to the pull of the magnet in the 
coil, battery consumption will be greatly les¬ 
sened. The slightest current should separate 
the contact points. 

Gasoline Pipe Broken. When the gasoline 
pipe breaks, a short piece of rubber tubing 
forced over the broken ends will do for a short 


60 


The Automobile Handbook 


time, but as gasoline attacks the rubber, too 
much dependence should not be put on it, and 
the pipe should be brazed at the nearest shop. 
If the hole is only a small one a piece of soap 
squeezed in and held in place by a soaped rag 
and string will serve if gravity feed is used. 
For pressure tanks a piece of rubber tubing 
split lengthwise and well soaped will tempora¬ 



rily stop the hole, if wired tightly around the 
pipe, but the pressure must be kept low, other¬ 
wise the rubber tubing will be loosened and the 
leaking commence again. 

A leak is sometimes hard to locate, but if the 
pipe is rubbed with soap suds, and then blown 
through, the leak will be located by the bubbles. 

Gear Teeth Broken. If several teeth are 



The Automobile Handbook 


61 


wholly, or partly broken they may be repaired 
in the following manner; referring to Fig. 11: 
Shape out a dovetail recess across the face of 
the wheel, cast or shape up a brass, bronze, or 
steel segment and dovetail it in, driving it tight 
from one side, and securing it with screws. 
Then file the teeth to a template made from the 
standing teeth of the wheel. For a single tooth 
proceed in the same way, no screws being neces¬ 
sary if properly fitted and the ends peened over 
with a hammer; or, file down the broken tooth 
flush with the bottom, drill and tap two or 
three holes, according to the width of the wheel, 
screw in capscrews and trim with a file. It 
might be well to add, when removing a timing 
gear for repairs, or any other purpose, care 
should be taken to see that it, and the gears 
with which it meshes, are plainly marked. 

Miss Fire Cylinder. Should one of the cyl¬ 
inders miss some of its regular explosions at 
intervals when under a load, it may be located 
by stopping the engine, and touching each cyl¬ 
inder with the business end of an unlighted 
match. The cylinders that have been doing 
their regular work will be hot enough to ignite 
the match, while the missing cylinder will not. 

Nuts and Screws —How to Loosen. Refrac¬ 
tory nuts may be loosened by heating, by means 
of a red-hot piece of iron held on or near them 
for a few minutes. This will expand the nuts 
and they will then come off readily. When a 
screw cannot be readily loosened with a screw- 


62 The Automobile Handbook 

driver, the latter should be pressed hard into 
the slot, while a helper applies a monkey wrench 
to the flat part of the blade. A tight radiator 
cap can be moved by winding a quantity of 
twine, or cloth tightly around it. 

Priming. If a motor does not start readily, 
due to not getting a rich enough mixture at 
slow speed of cranking, tie a small bunch of 
waste with a wire close to the air intake of the 



Fig. 12 

Section of Radiator Showing Washers Held by Wires on 
Stick, To Stop Leak 

carbureter, then prime by saturating the waste 
with gasoline. The added vapor will make 
starting easy. 

Radiator Leaking. In case a “honeycomb ’ 9 
radiator starts leaking at the end of a cell, and 
there is no radiator plug at hand,, a substitute 
may be made by passing a long bolt of small 
diameter through the defective cell and fitting 
each end of the bolt with washers made of 
leather, or rubber backed with iron washers or 



















The Automobile Handbook 


63 


metal strips, and then screwing down the nut 
until the leak is stopped. If a bolt cannot be 
obtained a small piece of wood may be whittled 
down to take its place, and the washers secured 
by means of copper wire as shown in Fig. 12. 


!iili 



If a leak occurs inside one of the cells, a square 
peg cut from soft wood, and covered with a 
piece of thin cloth smeared with white lead can 
be usedf as a plug. Only a moderate force 
should be used in these methods, as the tubes 













G4 


The Automobile Handbook 


are easily buckled. Leaks in gilled radiators 
may be stopped by applying a rubber patch held 
in place by tire-tape and wire. 

Rons or Links Broken. The repair of a 
broken link in the steering gear can be effected 
by placing the broken ends together and fasten- 





Fig. 14 


Valve Spring Strengthened by Inserting Metal Strips 

ing a rod or a piece of gaspipe against the link, 
winding the wire the entire length of the rod. 
If two hand vises can be obtained they can be 
attached as shown in Fig. 13. The rod is tied 
to the joined ends of the link with wire, and the 
hand vises screwed down on both link and rod. 
Anything but slow running with either of these 





















The Automobile Handbook 


65 


repairs is out of the question. Any other rod 
can be similarly repaired provided there is room 
for the pipe or the vises alongside of it. Wire 
cable can be substituted for brake rods, but the 
brake must be kept clear of the drum by some 
means when not in use. 

Squeaking Springs. A frequent source of an¬ 
noyance is the squeaking caused by the leaves of 
the springs having become dry from want of lu¬ 
brication. When such is the case, jack up the 



Fig. 15 

Method of Testing Valve Springs 


car until the wheels are clear of the ground, 
and the springs quite free. Then with a thin 
cold chisel, or a large screwdriver, gently force 
the leaves apart, one by one, and spread a mix¬ 
ture of vaseline, oil and graphite between them, 
using an old table knife or thin wooden paddle 
for the purpose. Where parts cannot be 
reached in this way, oil should be squirted in, 
and if necessary the leaf clips may be removed 
to allow of this being done. 

Trembler Blades Broken. Corset steels may 





66 


The Automobile Handbook 


be used as blades for trembler coils, by cutting 
them to the proper length, and riveting the 
platinum button from the broken blade through 
the hole which is punched near the end. After 
making the holes for the retaining screw, the 
blade is complete. A piece of the main spring 
of a clock will also make a good blade. 

Twine Is Useful in Breakdowns. Autoists 
should always carry 15 or 20 yards of strong 



twine in their kit, as it may be put to various 
uses about the car, such as reinforcing weak 
spots in tires, protecting chafed wires, and bind¬ 
ing together split sections of the steering wheel. 
Twine may also be used as a substitute in the 
absence of a lock washer, by forming a loop 
slightly larger than the diameter of the nut, 
and then wrapping twine around this loop, 
forming a “ grommet/’ as sailors call it. When 



















The Automobile Handbook 


67 


the nut is screwed down upon the grommet it 
will be held as firmly as if fitted with a nut- 
lock, and will stay tight until the twine rots. 

Axles, Definitions of. The following defini¬ 
tions apply to the forms of rear axles that are 
now and have been in use on shaft-drive cars. 

A “live axle” (no longer used) is one in 
which the driving member is carried by a bear¬ 
ing at each end, the outer end carries the wheel 
and the inner end the differential. 



Semi-Floating Rear Axle 


A “semi-floating axle, ” Fig. 17, is one in 
which the driving member is carried on one 
bearing at its outer end and with the inner end 
supported by the differential. The outer end 
carries the wheel. 

A “three-quarter floating axle,” Fig. 18, is 
one in which the driving member is carried by 
the differential at its inner end and at the outer 























68 


The Automobile Handbook 


end is carried by the hub flange, the flange itself 
being bolted to the wheel. The wheel is then 
carried by a bearing that runs on the outside of 
the end of the axle housing tube. 



the driving member is carried by the differential 
at its inner end and at the outer end is carried 
by a jaw clutch, the clutch itself being engaged 

















































The Automobile Handbook 


69 


with and meshing with the wheel hub. The 
wheel is then carried on two bearings that run 
on the outside of the axle housing tube. With 



Fig. 19 

Full-Floating-Rear Axle With Annular Ball 
Bearings 

this construction, the drive shaft may be entirely 
withdrawn from the car without disturbing the 
wheel or other axle parts. 





























70 


The Automobile Handbook 


Axle, Front. So far it has not been found 
practical to combine the tractive and steering 
functions of an Automobile in one set of wheels 
and axle. Therefore it is necessary to use a 
rigid front axle with knuckle jointed spindles, 
for steering purposes, and utilize the tractive 
power of the rear wheels only to propel the 
car. Some of the earlier forms of steering 
axles had the wheel pivots inclined so as to 
bring the projection of the pivot axis in line 
with the point of contact of the wheel with the 
ground, but as such constructions have not 
proved satisfactory they have in most cases 
been abandoned. 



Fig. 20 


















‘The Automobile Handbook 


71 


Front Axles. Figures 20 and 21 show four 
styles of front axles with steering-pivot ends: 
A shows a solid axle of square section, with 
the steering-pivot jaws and axle proper, of a 
single forging—B represents an axle of tubular 
cross-section with the steering-pivot jaws bored 



Fig. 21 


out to receive the tubular axle which is firmly 
brazed therein—C shows another style of tubu¬ 
lar axle, in which the steering-pivot jaw ends 
are turned down to fit the inside diameter of 
the tube and are also brazed in position, while 
D illustrates a one-piece axle with vertical hubs 
























72 


The Automobile Handbook 





[ STEERING KNUCKLE 







































The Automobile Handbook 


73 



Fig. 23 





































The Automobile Handbook 



BEARING AXLES 





















































The Automobile Handbook 


75 


instead of jaws, which carry L-shaped steering- 
pivots, instead of the usual form of knuckles. 

Steering Knuckles. In order to obtain ease 
of operation and secure the shortest turning 
radius with the least movement of the steering 
wheel or lever, the knuckle of the steering pivot 
should be as close to the center of the wheel 
as is possible. It is also cf great importance 
that the steering knuckles should be as heavy 
as is practically consistent with the size and 
weight of the car for which they are intended. 
If this imporant point be neglected, rapid wear 
and probable fracture of the knuckles may be 
looked for. 

A steering knuckle with a spindle and pivot 
of T shape is shown in Figure 22. The spindle 
and pivot N and the steering arms 0 are usually 
a one-piece forging. The steering arms O are 
connected by means of a suitable distance rod 
and the steering lever P is attached to one of 
the pivots N by turning a shoulder upon it and 
pinning and brazing the steering lever and pivot 
hub together. 

Figure 23 shows a steering knuckle with 
spindle and pivot of L shape. The steering arm 
R goes on the lower end of one pivot Q only, 
the other pivot having the combined steering 
arm and ever S on its lower end. The steering 
arms being detachable, the device may be oper¬ 
ated' from the right or left hand side by simply 
exchanging the levers R and S. The steering 
lever S has a ball upon its outer end to fit in the 


76 


The Automobile Handbook 


















































The Automobile Handbook 


77 


socket on the connecting rod of the steering 
mechanism. 

Axle, Rear. A live axle is any axle contain¬ 
ing parts which turn the wheels in addition to 
carrying weight. 

Dead Axle. A dead axle is an axle which 
carries weight only. 



Bevel Gear 


Pig. 26 

Two-Speed Rear Axle With Two Bevel Gears and 
Two Pinions 

Floating Axle. A special type of live axle 
in which the shaft that turns the wheels is in¬ 
dependent of the axle proper, and may be re¬ 
moved without affecting the axle’s weight car¬ 
rying capacity. 

In Fig. 24, K and L show respectively a 
live solid rear axle and a rigid tubular axle, 























7 $ 


The Automobile Handbook 


equipped with roller-bearings. The spring lugs 
form part of the roller-bearing boxes of the live 
axle, while they are usually brazed to the tubu¬ 
lar axle near its outer ends. 

A rigid tubular axle with ball-bearing live 
driving shaft is illustrated in Figure 27, the ball- 
cup or race is adjustable by means of a hexa¬ 
gon upon its outer extension in the rear of the 
hub of the wheel and is held securely in position 



and prevented from turning by means of the 
clamping device shown on the upper portion of 
the bearing. No separate adjustments for the 
inner two sets of ball-bearings are necessary, 
as the teeth of the spur gears of the differential 
which are keyed to the inner ends of the divided 
driving shaft, being free to slide upon them¬ 
selves, allow the shafts M to have a slight longi¬ 
tudinal movement within the axle tube, thus 



















The Automobile Handbook 79 

taking up the wear of each pair of ball-bearings 
with a single adjusting mechanism. 

In any style of full-floating axle the en¬ 
tire weight of the rear end of the car is car¬ 
ried on the axle housing, or casing, leaving the 
drive-shafts in the axle with no other work than 
that of revolving the wheels. In this axle, by 
the removal of the hub caps, the drive-shaft in 
each half of the axle can be pulled out, owing 
to its being free in the housing, and having gen¬ 
erally a squared end which fits into the bevel 
gears of the differential. In a semi-floating rear 
axle the complete car weight at the rear is car¬ 
ried on the axle housing, identically as in the 
floating axle, but the drive-shafts of the axle 
are not removable by pulling endwise through 
the hub. This is because these shafts are tightly 
keyed at their inner ends with differentials, 
bevels or, as is the case in one or two cars, the 
bevel gear is formed integrally with the shaft. 

The newest type of floating axle is that known 
as “three-quarter floating.” As will be seen 
from the definition on a preceding page, this 
form combines several of the advantages of both 
of the other types, while, of course, having cer¬ 
tain disadvantages of its own. 

The construction used in Fig. 28 shows a 
full-floating type of live rear axle in which the 
bearings are of the annular type, and the driv¬ 
ing jaws at the ends of the shafts engage with 
the hub in a proper manner to abort failure 
from lost motion. 


80 


The Automobile Handbook 


In this case the tube is reduced in diameter 
to take the bearings, and the shoulder so 
formed is taken advantage of in the process of 
providing for thrust. The shaft has no work to 
do excepting to take torsional moments, and 



of steel and drawn-steel parts. The inner race 
of the ball bearings is a sufficiently heavy tube, 
but it is not shaped in such a way as to act as a 
“preventer bearing,’’ hence complete depend¬ 
ence is placed on the ball bearings and they are 









































The Automobile Handbook 81 

made large enough to take the responsibility. 

Axle, Rear, Three-Quarters Floating. In 
this design, Fig. 18, the axle housing is ex¬ 
tended outward to a point in line with the out¬ 
side surface of the wheel, and the outer end is 
made of a diameter just large enough to allow 
the axle shaft to pass through it. Mounted on 
the outer end of the axle and directly in the 
center of the wheel is a single hearing, usually 
of the annular ball type. The wheel spokes are 
mounted in the hub flange in the usual manner 
and the flange is carried upon the outer surface 
of the bearing mentioned above. A large hub 
forging is bolted to the wheel flange and the 
bolts pass through the spokes which hold the 
brake drum on the inside. The outer end of 
the driving shaft is fastened into this hub forg¬ 
ing by a key way and taper; the inner end of 
the driving shaft is carried by the differential 
in the same manner as with a full floating type. 
It will therefore be seen that the radial load of 
the wheel is carried on the single bearing at 
the end of the housing, and this hearing is also 
required to carry the end thrust. The binding 
strains that are imposed upon the wheel when 
turning corners, for instance, are provided for 
through the rigidity of the driving shaft, which 
is fastened solidly into the wheel hub at its 
outer end and which is carried by the differen¬ 
tial at its inner end. This gives a leverage equal 
in length to the distance between the outer bear¬ 
ing and point of support in the differential. 


82 The Automobile Handbook 



Diagram Illustrating Theory of Back Firing 

























































The Automobile Handbook 


83 


Backfiring, Causes of. This is a term applied 
to an explosion or impulse which forces the 
flywheel of a motor suddenly backwards, that 
is, in the opposite direction to its proper rota¬ 
tion. The term is sometimes used in connection 
with explosions which occur in the muffler from 
the ignition of an accumulation of unburned 
gases. 

When a back kick occurs and the crank-shaft 
rotates in the reverse direction, that rotation 
must first be stopped and a rotation started in 
the correct direction. To stop the back kick or 
reverse rotation requires power, and to again 
start the correct rotation calls for power. The 
forces that stop the back kick are, the arm of 
the person cranking the weight of the rotating 
flywheel, and forcing one of the other pistons 
to compress the mixture. The force that starts 
the flywheel in the correct direction is the ex¬ 
ploding charge of gas in cylinder No. 2 as 
illustrated in Fig. 29, in which the piston in 
No. 1 cylinder has not reached the top dead 
center on the compression stroke when the 
spark occurs and the reverse movement of the 
crankshaft starts. In tracing out what happens 
the valve locations must be considered. Both 
valves—intake and exhaust—in No. 1 cylinder 
are closed on the compression stroke and they 
will, remain closed on the back kick stroke. 
Had the motor been running, No. 2 cylinder 
would have been going down on the explosion 


84 The Automobile Handbook 

stroke of the piston, but as there was no previ¬ 
ous explosion, the motor having been idle, the 
cylinder would be filled with mixture, with 
both valves closed, as they always are on the 
explosion stroke. The piston in this cylinder 
was normally going down; but, as soon as the 
back-fire occurred, the piston would start up 
and the valves remaining closed, the mixture 
would be compressed. This pressure would help 
to stop the back kick, and as soon as the power 
of back-kick was over the compression would 
start the piston down on the proper explosion 
stroke, which would prove of sufficient power 
to carry the motor past the firing point in the 
other cylinders. Cylinders 3 and 4 would not 
be factors at all, in that the piston in No. 3 
would, when the back-kick occurred, be near 
the bottom or end of the suction stroke with the 
intake valve open, and when the reverse action 
of the piston set in it would start rising, simply 
driving the mixture out through the open intake 
valve and through the carbureter. Cylinder No. 
4 was near the completion of the exhaust stroke 
when the back-fire started, and the exhaust 
valve was open. During the reverse motion 
caused by the back fire, the piston would start 
descending, the exhaust valve remaining open, 
exhaust gases would be drawn into the cylinder 
from the exhaust pipe. 

Other causes of back firing are, 

(1) A weak mixture. Bearing in mind that 
the mixture is the fuel of the engine, and that 


The Automobile Handbook 


85 


as in a stove, the character of the fuel influences 
its manner of burning, it will be evident that 
like poor wood, slaty coal, or other imperfect 
fuel, a weak mixture is a slow burner. This is 
point number one. Proportionate to the speed 
at which it is running, the motor has a certain 
sharply defined period of time in which it must 
complete each part of its cycle, if it is to operate 
satisfactorily. Should the parts of the cycle 
lap, or run over into one another, there is bound 
to be a hitch of some kind. The use of a very 
weak mixture causes just such a hitch by rea¬ 
son of the fact that it continues burning for 
some time after the completion of the part of 
the cycle during which it is supposed to func¬ 
tion, i. e., the power stroke. In fact, it is still 
burning when the inlet valve opens to take in 
a fresh charge, and as its burning in the cylin¬ 
der maintains considerable pressure therein, the 
latter, on the lift of the inlet valve, escapes 
through it and the carbureter with a pop, 
exactly similar to that of an unmuffled exhaust 
except that it is weaker. The remedy is more 
gas or less air, or sometimes both, and to find 
out just how much of each is required, start 
the motor and very gradually cut down its 
gasoline supply at the needle valve of the car¬ 
bureter until the motor begins to miss. Then as 
slowly increase the supply until the motor will 
run steadily and without missing on the mini¬ 
mum opening of the needle valve. Lock the 
latter in place. Then speed the motor up by 


86 The Automobile Handbook 

opening the throttle and adjust the spring of 
the auxiliary intake on the carbureter until the 
motor is receiving sufficient air to enable it to 
run and develop plenty of power at all speeds. 

(2) An overheated combustion chamber, 
due to a poor circulation of the cooling water—■ 
causing self-ignition of the charge before the 
proper time. 

(3) Advancing the ignition point too far 
ahead when the motor is running slowly under 
a heavy load—flywheel has not sufficient mo¬ 
mentum to force the piston over the dead cen¬ 
ter, against the pressure of the already ignited 
and expanding gases. 

(4) The presence op a deposit of carbon 
(soot) or a small projecting surface in the com¬ 
bustion chamber which may become incandes¬ 
cent and cause premature ignition. 

Batteries. But two forms of batteries are 
used in automobile work, the dry cell and the 
storage battery. Both are described in the fol¬ 
lowing pages. A distinction should be noted be¬ 
tween battery and cell. A single unit, complete 
in itself and capable of giving a flow of current, 
whether of the dry or storage type, is a cell. 
The ordinary dry cell gives a voltage of iy 2 
while a storage cell gives approximately 2 volts. 
When it is desired to secure higher voltages, two 
or more cells are used in conjunction with each 
other and the set then becomes a battery. A 
single cell is not a battery. 


The Automobile Handbook 87 

Batteries—Dry. A dry battery of the usual 
type consists of a zinc cell which forms the 
negative element of the battery. 


+ 



Fig. 31 

Section Through 
Dry Cell 


Dry Batteries are very generally used on 
moderate speed and low-priced cars. They are 
simple in construction, comparatively simple in 
operation, and their action is easy to under¬ 
stand. Each cell is composed of three elements: 
The carbon, the zinc, and the electrolyte. The 
carbon usually takes the form of a round stick 
placed in the center of a cylindrical vessel made 
of zinc in sheet form. The space between the 
carbon and the zinc is filled with the electrolyte, 




















88 The Automobile Handbook 

generally a solution of sal-ammoniac, which is 
poured in on crushed coke. The top is closed, 
or rather sealed, with pitch to prevent the loss 
or evaporation of the liquid. Through this, 
project the ends of the carbon and the zinc, these 
being formed into binding posts for holding the 
wires. As this holding of the wires must be an 
intimate relation, the usual form is a threaded 
shank upon which a pair of nuts are mounted. 
Between these the wire to be connected is 
crushed or compressed by the moving together 
of the nuts. 

The two poles or binding posts are called the 
positive and the negative, and are indicated by 
the + sign for the former and the — sign for 
the latter. Carbon being the positive element, 
the + sign attaches to it. Now, the act of con¬ 
necting these terminals together so as to allow 
a flow of current allows of two different meth¬ 
ods of procedure, a right and a wrong way, it 
is true, but that was not what was meant. 

In one respect dry batteries have a decided 
advantage over storage batteries for ignition 
purposes, from the fact that on account of their 
high internal resistance they cannot be so 
quickly deteriorated by short circuiting. 

On account of this high internal resistance, 
dry batteries will not give so large a volume of 
current as storage batteries, but a set of dry 
batteries may be short circuited for five min¬ 
utes without apparent injury and will recuper¬ 
ate in from twenty to thirty minutes, while a 


The Automobile Handbook 89 

storage battery would in all probability be 
ruined under the same conditions. 

It is often desired to secure a greater voltage 
than one cell will give, or else to secure a source 
of current that will give a greater time of ser¬ 
vice than can be secured from the single cell. In 
either case, it is customary to combine two or 
more cells in certain definite combinations and 
connect them with each other in such a way 
that the desired voltage or length of life is 
realized. It is possible to make such combina¬ 
tions by using either dry or storage cells, 
although storage cells are usually boxed after 
forming. 



Fig. 32 

The Ordinary Battery Connection, in Series 
Two methods are usually employed, viz.: 
series, and multiple, or parallel. To connect 
dry batteries in series, the terminals are joined 
alternately, that is, the zinc of the first is con¬ 
nected to the carbon of the second, the zinc of 
the second to the carbon of the third, etc. 

When so joined, the positive element is left 
free at one end, and forms the positive terminal 









so 


The Automobile Handbook 


of the group, which is then considered as a unit. 
The other free end (the negative) forms the 
negative terminal of the unit, see Fig. 32, which 
shows four cells connected in series. 

Figure 33 shows four cells connected in paral¬ 
lel which means that all of the positive termi¬ 
nals are connected to one common wire, and all 
negatives are connected to another wire. 

This mode of wiring up the cells gives a 
smaller output for the group. Thus if the in¬ 
dividual batteries have an internal resistance 



which is low in comparison with the external 
resistance, the total output will be but slightly 
more than that of a single cell. If, on the other 
hand, the internal resistance is high relative to 
the external, the current will be roughly pro¬ 
portional to the number of cells. 

Where the cells are divided into sets or groups 
of a small number (four is usual), and more than 
one of these sets are used at a time, there are 
again two methods of joining them. These two 
are the same as before, viz., series and multiple. 







The Automobile Handbook 


91 


The former is very seldom used, if ever, but the 
other is rather common. When two or more 
sets of batteries, themselves connected in series 
are, as sets, joined in multiple the whole is 
spoken of as connected in series-multiple. 



Fig. 34 


Batteries—Storage. A storage battery as 
used in ignition service, is usually of the lead- 
acid type, in which the electrolyte is sulphuric 
acid and water of a density about 1.2— specific 
gravity. The plates are of two classes—posi¬ 
tives and negatives—there being one more nega¬ 
tive than positive in each nesting in a ceil. 
The elements of a cell of storage battery are 



































92 


The Automobile Handbook 



given in Fig. 35, and consist of the following: 
Positive plates A, of which there is one fewer 
than of negatives; negative plates B, of which 
there is always one more than positives; sepa- 


Fig. 35 

Elements of Assembled Battery 

rators C, which may be of wood, rubber, oi 
other suitable material, and if of wood must be 
treated; positive strap D, the function of which 
is to connect all the positive plates, across the 














The Automobile Handbook 


93 


top, into electrical relation; negative strap E, 
the function of which is to connect all the nega¬ 
tive plates, at the top, in electrical relation; bat¬ 
tery jar F, made of rubber composition, light, 
strong and acid proof; cover for the jar G, with 
holes for the terminals of the elements, and a 
vent; assembled cell of battery H, showing the 
elements in place, separated, with cover on; 
ready for connections; and a battery box I, of 
oak, usually contrived to hold three cells of 
battery, sometimes two. 

The positive and negative plates, called ele¬ 
ments, consist essentially of a grid in each case, 
made of lead-alloy, in which antimony is used 
to engender stiffness. The grids are in divers 
forms, depending upon the views of several 
makers, the idea being to afford space for the 
active material, and to lock the same in, so that 
it will not drift out, as it is prone to do, under 
the action of the charging, and discharging cur¬ 
rent. Surface is the great requisite, and it is 
the aim to afford the maximum area of the fin¬ 
ished plates, per pound of active material used; 
limiting the weight of the supporting grid, in 
so far as it is possible to do so. 

The voltage of a battery of this type is usu¬ 
ally 2.2 volts when the circuit is closed, but it 
drops to 2 volts within the first hour of using, 
which pressure it usually maintains during the 
next 5 hours, after which the voltage declines 
at a rapid rate. 

Adding Water to Cells. In service water 


94 


The Automobile Handbook 


will have to be added to the cells to compensate 
for evaporation, and for the loss that takes place 
during charge, brought about by the entraining 
of water with the bubbles of gas that shoot off 
and out of the jars, if they are open, that is to 
say, if the covers are removed before and left 
off during charging, which is not usually the 
case. The result in any event is in favor of in¬ 
creasing strength of the electrolyte, and water 
will have to be added from time to time in order 
that the plates may not be exposed to the atmos¬ 
phere above the line of active material; which 
is a point that must be cared for if the battery 
is to last for a long time. The water so added 
should be pure—distilled—and the right quan¬ 
tity to add, will be determined by means of a 
hydrometer placed in each cell between the sepa¬ 
rators if there is sufficient room, or the electro¬ 
lyte may be withdrawn through the utility of a 
gun made of hard rubber with a long slender 
neck. The test should be made when the bat¬ 
tery is charged and every cell should be exam¬ 
ined rather than to test one cell and conclude 
that all are in an average condition. 

Storage Batteries—Care of. Among the 
troubles that ultimately attend batteries in serv¬ 
ice the following are the most conspicuous: 

Hardening of negative elements; local action; 
buckling of plates; shedding of active material; 
sulphation; reversal of negative elements; dis¬ 
integration of grids; protruding active mate¬ 
rial; deformation of separators; broken jars; in- 


The Automobile Handbook 


95 


eipient short circuits; defective electrical con¬ 
tact: loss of capacity; loss of voltage; corrosion 
of plates, and needle formations. 

Hardening of the negative elements will fol¬ 
low if they are exposed to air, as when the elec¬ 
trolyte is allowed to fall below the level of the 
plates, from any process that will produce over¬ 
oxidization if the temperature is allowed to in¬ 
crease much above 90 degrees Fahrenheit. 
When the negative elements are hard, to reduce 
them back to the normal condition, assuming 
the process is not too far gone: Remove the 
elements from the jar, place the negatives in a 
cell, with dummy positives, and charge until 
the negatives are corrected, taking care not to 
charge at a too high rate. High temperature 
and excess boiling should be avoided. If the 
negatives are charged in their own cell with 
the regular positives the positives will be dam¬ 
aged by the excess charging that will be neces¬ 
sary to reduce the negatives. When the nega¬ 
tives are sufficiently charged to correct the evil 
they may be returned to their own cell, and 
when connected up with the positives the cell 
will be ready to go into service again, if in the 
meantime the positives are given such attention 
as their condition would seem to indicate. Local 
action, following impurities in the electrolyte, 
will only be prevented as much as it is possible 
to do so when the electrolyte is removed and 
pure electrolyte substituted in its stead. This 
should be done when the cells are fully charged. 


96 


The Automobile Hcmdbook 


The electrolyte will hold most of the impurities 
when the battery is in the fully charged state. 

Buckling of plates, when batteries are defec¬ 
tive in design, rather than in cells of normal 
characteristics, is a trouble that will follow in 
any cell if the discharge is allowed to extend 
below 1.8 volt as indicated by the cadmium test, 
rather than by the usual potential difference 
reading across the two sets of elements in the 
cell. If the rate of discharge is excessive, a 
condition that is not likely in ignition work, 
buckling will follow also. Short-circuiting the 
elements to see if the battery is alive will tend 
to buckle the plates, due to the heavy discharge, 
and the uneven rate of discharge over the sur¬ 
faces of the elements. In defective construction, 
if the active material is not of the same porosity, 
thickness, and in the same condition all over the 
surfaces of the plates, buckling will follow. 

Shedding of the active material, to a slight 
extent, is a normal condition of batteries; and 
to prevent trouble due to incipient short cir¬ 
cuits, such shedding is cared for by having a 
space in the bottom of cells to hold such 
shedded material. When elements are of in¬ 
ferior design and improperly constructed the 
active material will shed at a rapid rate, and 
the user of the battery can do nothing more than 
demand a new battery to replace the defective 
one. If charging is done at a too rapid rate 
the active material will be loosened by the rap¬ 
idly escaping gas, and even on discharge, if the 


The Automobile Handbook 


97 


rate is high, the shedding of active material is 
likely to follow. 

Sulphation, which is a normal expectation 
during discharge of a battery, introduces serious 
complications under certain conditions as when 
the active material is not in intimate contact 
with the grids thus allowing the electrolyte to 
get between the grids and the active material, 
with the result that sulphate, which is a high 
resistance material, isolates the grids and re¬ 
duces the efficiency of the cell in two ways; 
first, by increasing the ohmic losses, and, second, 
by lowering the chemical activity. Excess sul¬ 
phate is prone to form when the electrolyte is 
out of balance, and one of the best ways to 
abort this action is to keep the electrolyte with¬ 
in the prescribed limits of strength. If sulphate 
is allowed to form until white crystals show over 
the surfaces of the plates, it is highly improb¬ 
able that the cells will ever be of sufficient serv¬ 
ice to warrant continuing them in service. The 
only way to afford relief lies in reducing the 
growth of sulphate by continuous charging the 
sick elements in a cell with dummies until the 
sulphate is reduced. A slow rate for a long 
time may bring about a reform. 

Negative elements to be reversed must be 
below capacity, or the cells must be discharged 
to zero and then reversed. In charging it is 
always necessary to make sure that the connec¬ 
tions are made in such a way that current will 
flow into the battery, rather than out of it. Volt- 


98 


The Automobile Handbook 


meters in which permanent magnets are used 
will serve as polarity indicators, and with them 
it is possible to proceed with safety. If a bat¬ 
tery is connected up in reverse when it is put on 
charge, instead of being charged it will be dis¬ 
charged, and then charge in reverse. While it 
is discharging it will deliver current to the line. 

Disintegration of grids will follow if the im¬ 
purities are allowed to enter the electrolyte, as 
iron, etc. Continued charging will also have 
the effect of reducing the grids to form salts 
of lead. 

Protruding active material, due to expansion 
and displacement of the same, indicates a lack 
of binding relation between the grids and the 
active materials. There is no remedy. Defor¬ 
mation of separators, when they are made of 
rubber compound, follows when the cells are 
allowed to heat beyond a certain point. This 
trouble will be aborted if the cells are charged 
at a normal rate, and if the temperature is not 
allowed to increase beyond about 90 degrees 
Fahrenheit. When wood separators are used 
they will slowly rot and in time it will be neces¬ 
sary to replace them. 

Broken jars will allow the electrolyte to leak 
out, and frequently the fracture is but a minute 
crack, so that it is well to be on the lookout 
for just this kind of trouble. If the jars are 
properly nested and motion between them is 
prevented they will as a rule serve without 
breaking. 


The Automobile Handbook 


99 


Incipient short circuits are likely to go un¬ 
noticed. They are generally due to detached 
particles of active material that lodge between 
the plates, especially in vehicle and ignition 
types-, owing to the short distance separating 
the plates, and the use of separators, such as 
perforated rubber in the absence of wood, which 
have the virtue of being porous but too close to 
allow the active material to bridge across the 
space between the plates. 

Defective electrical contact is due to corrod¬ 
ing of joints that are not made by burning. 

Loss of capacity may be traced to such causes 
as: If the electrolyte is out of balance or below 
the level of the top of the plate; loss of active 
material from the grids; sulphate formed on 
the surfaces of the grids, isolating the active 
'' material; lack of porosity of the active material; 
impurities and sulphate clogging up the pores 
of the active material; low temperature; high 
temperature ; persistent sulphation, and inter¬ 
cell leakage due to electrolyte spilled over the 
surfaces, especially if jars are in actual contact 
with each other. 

Loss of voltage, as distinguished from loss of 
capacity, follows in a battery when one or more 
of the cells are dead or below voltage. If one 
or more of the cells are reversed they will set up 
a counter-electro-motive force, and the over-all 
reading of the battery will be reduced accord¬ 
ingly. The remedy is obvious. All the cells 


100 


The Automobile Handbon■ 


should read the same way, and all should have 
the same difference of potential, respectively. 

In view of the sulphated condition that at¬ 
tends all batteries that are discharged at a low 
rate for a long time, as is the case in ignition 
work, it is necessary to charge at a low rate for 
a long time in order to reduce the sulphate, 
which is in persistent form and very difficult 
to reduce. It will not be enough to correct the 
strength of the electrolyte once during the 
charging process for the reason that it will be 
difficult, if not impossible, io ascertain the con¬ 
dition of the same with any degree of accuracy, 
and the necessity for noting strength two or 
three times in the act of charging is apparent. 
When the battery is fully charged, which may 
take even sixty hours of continuous charging 
at a low rate, the electrolyte in every cell should 
stand at full strength, considering a state of 
full charge, and the color as well as other indi¬ 
cations of a full charge should be fully noted. 
Boiling at a slow rate should be tolerated for 
several hours, but the temperature should be 
held at about 90 degrees Fahrenheit during the 
entire time. If a battery is charged at frequent 
intervals it will last longer in service, give less 
trouble in charging and will be more reliable in 
service. It is well to begin charging directly a 
battery is taken out of- service as any delay 
after that time will result in a marked deteriora¬ 
tion of the cells. 

When a car is put out of commission, even 


The Automobile Handbook 


101 


for a few weeks, the battery should be given a 
light discharge, and a subsequent charge as 
often as once a week, until it is again brought 
back into use. 

Storage Batteries — Charging. Positive 
plates in the charged state are of a velvety 
brown or chocolate color; negative plates have 
the color of sponge lead, which is very nearly 
light gray. When a battery is approaching a 
condition of full charge the color tones up quite 
noticeably, and it is possible to mistake a con¬ 
dition of full charge, if color alone is taken as 
the evidence; the exterior will have the appear¬ 
ance of full charge, since the active material, 
on the exterior surface, will reach its charged 
form first; if the thickness of active material on 
the grids is very thickj as it is likely to be in 
low discharge rate work, charging by color, 
as evidence of a state of full charge, will be to 
limited advantage. Details regarding the 
proper care and upkeep of storage batteries are 
given in the following pages. 

Storage Batteries—Testing. Tests for im¬ 
purities in the electrolyte may be made as fol¬ 
lows. For iron; 

Neutralize a quantity of the electrolyte to be 
investigated, after diluting the same, by the 
addition of an equal amount of pure distilled 
water, using strong ammonia water for the pur¬ 
pose. To the solution, so neutralized, add one- 
thirtieth of the amount of the same of hydro¬ 
gen peroxide, thus reducing any iron present 


102 The Automobile Handbook 

to the ferric state. If a sample of this solution 
is rendered alkaline by the addition of a suffi¬ 
cient quantity of ammonia water, then, if iron 
is present, enough to amount to anything of 
great moment, from the battery point of view, 
a brownish red precipitate will form. A test 
for chlorine is as follows: 

Make a solution of nitrate of silver in the 
proportion of 20 grams of the same, in 1,000 
cubic centimeters of pure distilled water, and 
add a few drops of this solution to a small quan¬ 
tity of the electrolyte to be investigated; if 
chlorine is present the solution will turn white, 
owing to the formation of chloride of silver, 
which will precipitate out. 

A test for nitrates is as follows: In a test tube, 
holding 25 cubic centimeters of electrolyte to be 
tested, add 10 grams of ferrous sulphate; to 
this carefully add 10 cubic centimeters of chem- 
ically-pure sulphuric acid by pouring the same 
slowly down the side of the tube; in the pres¬ 
ence of nitric acid, a brown solution will form 
between the electrolyte to be tested, and the 
concentrated solution of sulphuric acid. 

The presence of copper may be detected from 
the fact that when ammonia solution is added 
to electrolyte, a bluish-white precipitate will 
form. In testing for mercury, lime water, if it 
is added to electrolyte in which mercury is pres¬ 
ent will evolve a black precipitate. Testing for 
acetic acid is as follows: To a small quantity 
of the electrolyte to be tested, add enough am- 


The Automobile Handbook 


103 


monia water to render the same neutral; ferric 
chloride added to this solution will cause the 
same to turn red in the presence of acetic acid 
and the solution will then bleach, provided 
hydrochloric acid is added, thus affording con¬ 
clusive proof of the presence of the undesired 
acetic acid. 



Battery, Storage, Starting and Lighting 
Types. The foregoing description and instruc¬ 
tions relating to storage batteries apply equally 
well to ignition, starting and lighting types. 
The following rules include the standard bat¬ 
tery instructions adopted by the Society of 
Automobile Engineers for the installation and 
































104 The Automobile Handbook 

care of batteries used in connection with elec¬ 
tric lighting and starting systems. 

Batteries must be properly installed. Keep 
battery securely fastened in place. Battery 
must be accessible to facilitate regular adding 
of water to, and occasional testing of, solution. 
Battery compartment must be ventilated and 
drained, must keep out water, oil and dirt and 
must not afford opportunity for anything to be 
laid on top of battery. Battery should have 
free air space on all sides, should rest on cleats 
rather than on a solid bottom, and holding de¬ 
vices should grip case or case handles. A cover, 
cleat or bar pressing down on the cells or ter¬ 
minals must not be used. 

Keep battery and interior of battery compart¬ 
ment wiped clean and dry. Do not permit an 
open flame near the battery. Keep all small 
articles, especially of metal, out of and away 
from the battery. Keep terminals and connec¬ 
tions coated with vaseline or grease. If solu¬ 
tion has slopped or spilled, wipe off with waste 
wet with ammonia. 

Pure water must be added to all cells regu¬ 
larly and at sufficiently frequent intervals to 
keep the solution at proper height. Add water 
until solution is level with inside cover. Never 
let solution get below top of plates. Plugs must 
be removed to add water, then replaced and 
screwed on after filling. The battery Should 
preferably be inspected and filled with water 
once every week in warm weather and once 


The Automobile Handbook 105 

every two weeks in cold weather. Do not use 
acid or electrolyte, only pure water. Do not use 
any water known to contain even small quan¬ 
tities of salts of any kind. Distilled water, 
melted artificial ice or fresh rain water are 
recommended. Use only a clean metallic vessel 
for handling or storing water. Add water regu¬ 
larly, although the battery may seem to work all 
right without it. 

The best way to ascertain the condition of 
the battery is to test the specific gravity (den¬ 
sity) of the solution in each cell with a hydrom¬ 
eter. This should be done regularly. A con¬ 
venient time is when adding water, but the 
reading should be taken before, rather than 
after, adding water. A reliable specific gravity 
test cannot be made after adding water and 
before it has been mixed by charging the bat¬ 
tery or running the car. 

To take a reading insert the end of the rub¬ 
ber tube in the cell. Squeeze and then slowly 
release the rubber bulb, drawing up electrolyte 
from the cell until the hydrometer floats. The 
reading on the graduated stem of the hydrom¬ 
eter at the point where it emerges from the 
solution is the specific gravity of the electro¬ 
lyte. After testing, the electrolyte must always 
be returned to the cell from which it was 
drawn. The gravity reading is expressed in 
“points ,’ 9 thus the difference between 1.250 
and 1.275 is 25 points. 

When all cells are in good order, the gravity 


106 The Automobile Handbook 

will test about the same (within 25 points) in 
all. Gravity above 1.200 indicates battery more 
than half charged. Gravity below 1.200, but 
above 1.150, indicates battery less than half 
charged. When the battery is found to be half 
discharged, use the lamps sparingly until the 
gravity is restored to at least 1.250. If by 
using the lamps sparingly, the battery does not 
come back to condition, there is trouble in the 
wiring or generator system which should be 
investigated and remedied immediately. Grav¬ 
ity below 1.150 indicates battery completely 
discharged or “run down.” A run down bat¬ 
tery is always the result of lack of charge or 
waste of current. If, after having been fully 
charged, the battery soon runs down again, 
there is trouble somewhere in the system which 
should be located and corrected. Putting acid 
or electrolyte into the cells to bring up specific 
gravity can do no good and may do great harm. 
Acid or electrolyte should never be put into 
the battery except by an experienced battery 
man. 

Gravity in one cell markedly lower than in 
the other, especially if successive readings show 
the difference to be increasing, indicates that 
the cell is not in good order. If the cell regu¬ 
larly requires more water than the others, thus 
lowering the gravity, a leaky jar is indicated. 
Even a slow leak will rob a cell of all of its 
electrolyte in time and the leaky jar should im¬ 
mediately be replaced with a good one. If there 


The Automobile Handbook 


107 


is no leak and the gravity is, or becomes, 50 to 
75 points below that in the other cells, a partial 
short circuit or other trouble within the cell is 
indicated. A partial short circuit, if neglected, 
may seriously injure the battery and should 
receive the prompt attention of a good battery 
repair man. 

A battery charge is complete when, with 
charging current flowing at the finish rate 
given on the battery plate, all cells are gassing 
(bubbling) freely and evenly and the gravity 
of all cells has known no further rise during one 
hour. The gravity of the solution in cells fully 
charged as above is between 1.275 and 1.300. 

If for any reason an extra charge is needed 
it may be accomplished by running the engine 
idle, or by using direct current from an out¬ 
side source. In charging from an outside source 
use direct current only. Limit the current to 
the proper rate in amperes by connecting a suit¬ 
able resistance in series with the battery. In¬ 
candescent lamps are convenient for this pur¬ 
pose. Connect the positive battery terminal 
(with red post, or marked P or +) to the posi¬ 
tive charging wire and negative to negative. 
If reversed, serious injury may result. Test 
charging wires for positive and negative with 
a voltmeter or by dipping the ends in a glass 
of water containing a few drops of electrolyte, 
when bubbles will form on the negative wire. 
When charging, start at the starting rate and 
continue the charge at this rate until the cells 


108 


The Automobile Handbook 


gas freely. Then continue the charge for six 
hours at the finish rate. The specific gravity 
at the end of the charge should read between 
1.275 and 1.300. If the specific gravity does 
not reach this point, continue the charge at the 
finish rate until the specific gravity stops ris¬ 
ing, which is an indication that the battery is 
fully charged. 

A battery which is to stand idle should first 
be fully charged. A battery not in active 
service may be kept in condition for use by 
giving it a freshening charge at least once a 
month, but should preferably also be given a 
thorough charge after an idle period before it 
is replaced in service. Disconnect the leads 
from a battery that is not in service, so that it 
may not lose charge through any slight leak 
in car wiring. 


The Automobile Handbook 


109 


Bearings, Ball. Ball bearings may be broadly 
divided into three classes—thrust, cone and an¬ 
nular. Thrust bearings are those intended to 
sustain end thrust, and in them care-must be 
exercised to see that the points of contact of 
the balls are exactly opposite, and that the 
grooves in which the balls run are formed to a 
sectional radius a little larger than that of the 
balls, thereby securing safe and easy move¬ 
ment of the balls. These grooves must be de¬ 
signed not only to give smooth rolling contact, 
but so that a measurable area of the ball’s sur¬ 
face contacts with the race. It is also possible 
for a thrust bearing to act at the same time as 
a radial bearing, in which case, however, the 
four-point system must be used. In thrust bear¬ 
ings the balls are constantly under pressure and 
table 5 gives suitable loads for equal shaft diam¬ 
eters and revolutions for different sizes and 
numbers of balls: 


table 5. 


Shaft 
Diameter, 
in inches. 

Allowable 

Load 

lbs. 

R.P.M. 

Number 

of 

Balls 

Ball 

Diameter 
in Inches 

2.55 

550 

500 

22 

% 

2.55 

1,000 

500 

15 

% 

2.55 

1,200 

500 

14 

11/16 

2.55 

1,300 

500 

13 

% 

2.55 

1,600 

500 

12 

Vs 

2.55 

1,800 

500 

10 

1 


The adjustable cone bearing, Fig. 39, has been 
used in millions of bicycles with excellent re¬ 
sults, but under large loads has been found in¬ 
adequate. A ball can roll freely only with op¬ 
posite points in contact, and every third or 










110 


The Automobile Handbook 


fourth point of contact involves more or less 
spinning, or sliding movement of the ball, which 
shortens its life, and the bearing must operate 
to the detriment of the contact surfaces. 

The third and great type of ball bearing is 
the so-called annular one intended for radial 
loads. It consists of three elements—two races 
and the balls. The new annular bearings re¬ 
quire no adjustment or fitting, and the rolling 
action of the balls takes place without interfer¬ 
ence of friction. A wonderful advantage of 
this bearing is that as high as 96 per cent of the 
space between ’the races can be filled with balls, 
the balls being introduced through filling lots 
whose size is a little less than the diameter of 
the balls to be introduced, so that the balls are 
forced between the two races under pressure 
and by virtue of the elasticity of the material. 
In the annular bearing but 30 per cent of the 
balls are under load at one time, and it is pos¬ 
sible for equal axle sizes and speeds to use dif¬ 
ferent dimensions and loading according to 
the size of the balls. Table 6 gives suitable 
loads for equal shaft diameter, and revolutions 
for various sizes, and numbers of balls. 


table 6. 


Shaft 

Diam. 

inches 

Allowable 
load on 
Bearing 1 , lbs. 

R. P. M. 

No. of 
Balls 

Diam. of 
Balls, 
Inches 

3.14 

1,000 

1 500 

I 20 

% 

3.14 

1,300 

| 500 

1 21 


3.14 

2,500 

| 500 

1 12 

l 

3.14 

3,000 

1 500 

1 14 

1 A* 

3.14 

4,500 

1 500 

1 11 

1 









The Automobile Handbook 


111 


Annular ball bearings are also made with two 
rows of balls, and in the majority of them each 
ball is in a separate cage. Experiments have 
proven that, where the balls contact with one 
another, after a few years the friction results in 
grooves being worn in them. In Fig. 37 is shown 
the form of separator used in the F. & S. bear¬ 
ings. If in the application of this bearing it is 



Fig. 37 

F & S Bearing Separator 


necessary to sustain heavy axle loads, it is ab¬ 
solutely necessary to add an independent thrust 
bearing, or to employ a combination bearing 
which takes the place of bolt thrust and radial 
loads. 

Ball Bearings —Two in One. Figs. 38, 39, 
and 40 illustrate a ball bearing manufactured at 
Bristol, Conn., which owing to its dual ability as 
























112 


The Automobile Handbook 


as expressed by its name (“two in one”) is 
especially adapted to automobile service. Its 
makers claim that it is able to withstand radial 
or thrust loads, or any combination of the two, 
with the use of but a single bearing with its 
attendant simplicity of mounting. In order to 
bring about this result, two rows of balls are 
employed in staggered relation to one another, 
and the ball races are so arranged that the line 



Fig. 38 

Assembled Bearing Complete 


of pressure is either at an angle of 45 degrees 
or 60 degrees with the horizontal, when the axis 
of rotation of the bearing is in a horizontal 
plane. 

Figure 38 shows the permanent assembly of 
the bearing, sufficient metal being provided in 
the shell to permit of drawing the latter tightly 
ove*- the cups. 



The Automobile Handbook 


113 


Figure 39 shows the various parts of this 
bearing, and Fig. 40 is a semi-sectional view 
showing the order of their assembly, from the 
shaft outward, as follows; the cone, the separa¬ 
tor, the two cups and the shell. It will be no¬ 
ticed that the line of pressure of the cone, cups, 



Fig. 39 


and balls is at an angle of 45 degrees with the 
horizontal, and this feature applies equally to 
both rows of balls, thus adapting the bearing 
to withstand a load from any angle. Two semi¬ 
circular races are turned in the cone to receive 
the balls, while the sheet metal separator is so 
stamped that the ball retaining notches are 







114 


The Automobile Handbook 


staggered with reference to each othef. These 
openings are made slightly larger than the ball 
diameter, so that the contact between the ball 
and separator is said to be a point contact at 
one end of the axis of rotation, while the weight 
by separator is carried on the balls at the top 
of the bearing. By maintaining the relative 
positions of the balls at all times, cross friction 



Fig. 40 

Sectional View of Bearing 


it is claimed is entirely eliminated, while the 
friction introduced by the use of the separator 
is practically negligible. 

Ball Bearings—Lubrication of. Ball bear¬ 
ings must be so housed in as to retain lubricant 
and exclude dust, grit, etc. An impression that 
ball bearings will operate without lubricant is 
quite general. It is barely possible that abso¬ 
lutely true spheres might roll on absolutely 


The Automobile Handbook 


115 


true surfaces if both were made of materials 
that were absolutely inelastic, and therefore 
would remain true under load. But since such 
absolute perfection of the shape is not to be had, 
some means must be taken to provide and re¬ 
tain lubricant. 

Rust and acid must be kept out of ball bear¬ 
ings. Experience and most carefully conducted 
tests have proven that long life under load can 
be realized from ball bearings only when the 
surfaces are not only true, but are also highly 
polished and smooth. Roughness will be broken 
down and leave still greater roughness. Rust 
and acid will destroy originally true and smooth 
surfaces. Since not a few lubricants contain 
free acids, care in their choice must be exercised. 
Plentiful lubrication and a properly closed 
/ mounting are safeguards against rust. 

In the lubrication of ball bearings it is advis¬ 
able to use vaseline; or, when a lubricant of 
greater body or stiffness is desired, to use a mix¬ 
ture of vaseline and some high-grade mineral 
grease. The grades known as semi-fluid are very 
well suited for this use and any combination 
may be used with success in such cases. 

Annular Ball Bearings. In the annular ball 
bearing, Fig. 42, a race of balls C is contained 
between an inner retainer A and an outer race 
B, there being grooves in the opposing surfaces 
of Ihese to receive the balls. In a Hess-Bright 


116 The Automobile Handbook 

bearing of this type, as illustrated in Fig. 41, 
the entire space between the races C and B is 
not occupied by balls, but is utilized in different 
ways. In this only enough balls to make a half 
circle in the bearing are used, and these are 
spaced apart by means of small helical springs. 
These springs contain oil pads of felt, and are 
headed by sheet-metal discs that extend far 



enough into the grooves to prevent sidewise dis¬ 
placement of the springs, wuthout, however, 
producing any more than a negligible friction. 
Assembling this bearing one race is placed ec¬ 
centric to another race and the requisite num¬ 
ber of balls slipped into positions, after which 
the races are made concentric and the balls reg¬ 
ularly distributed. This done, the separating 
springs with lubricating means are installed. 


The Automobile Handbook 


117 


Once the springs are in place the tension of them 
is such as to make the bearing self-contained. 



It is not practicable to disassemble or repair 
the various forms of annular ball bearings in 
the ordinary shop. These forms are not adjust¬ 
able and are not designed to be taken apart. 
It is quite possible to reform the races and to 
insert new balls when the bearing is badly worn 
or scratched, but such work must be done with 
machinery and tools especially designed for 
handling it. Ball bearing repairs are handled 
by various companies who specialize on such 
work and it will always be advisable to com¬ 
municate with one of them. 

Hard and Soft Bearings. There are two 
general classes of solid bearings, those which 
contain a large per cent of copper and a small 
amount of the softer metals; which are known 


118 


The Automobile Handbook 


as hard metals, as brass or bronze. Those which 
contain a large proportion of tin or lead and a 
small per cent of copper are known as soft 
metals—as babbitt-metal, anti-friction metal and 
white metal. 

In some instances and under certain condi¬ 
tions it has been found that a good close-grained 
cast iron makes an excellent bearing metal. 
Being of a granular nature, it has the property 
of retaining the lubricant in place, even when 
highly polished and under great pressure, with 



Fig. 43 Fig. 44 

Types of Plain Bearings 


a low co-efficient of friction, but is too brittle 
to withstand severe shocks. 

Plain Bearings. Plain solid bearings are 
used on many parts of an automobile, particu¬ 
larly in the engine and transmission bearings, 
although ball and roller bearings are taking 
their place in many constructions. The major¬ 
ity of the cars use brass, bronze or babbitt-metal 
on the main and crankshaft bearings, while ball 
and roller bearings are used on the transmission 
and wheel bearings. A typical plain bearing is 
shown in Fig. 43, in which A is the journal made 
of steel, while the bearing members shown at 










The Automobile Handbook 


119 


B. B. are made of either brass, bronze, or babbitt 
metal. Figures 44 and 45 show different types 
of connecting rod bearings. For plain-bear¬ 
ings, the shafts of which are continuously run¬ 
ning at a high rate of speed, such as motors 
and speed-change gears, the working pressure 



Fig. 45 

Solid Connecting Hod Bearing 

per square inch should not exceed 400 pounds. 
As the arc of contact or actual bearing surface 
of a journal bearing is assumed as one-third of 
the circumference of the journal itself, the pres¬ 
sure per square inch upon a bearing is therefore 
equal to the total load upon the bearing, divided 













120 


The Automobile Handbook 


by the product of the diameter of the journal 
times the length of the bearing. 

Let D be the diameter of the journal or shaft 
at its bearing, and L the length of the bearing, 
if W be the total load or pressure upon the bear¬ 
ing and P the pressure in pounds per square 
inch of bearing surface, then 

W 

P =- 

D X L 

If the total load or pressure on the bearing 
be known and the diameter of the shaft given, 
then the proper length of the bearing will be 

W 

L =- 

DXP 

If the length of the bearing be known and 
other conditions as before given, then the proper 
diamf ter of the journal will be 

W 

D =- 

PXL 





The Automobile Handbook 


121 


Bearing, Roller. A form of bearing used in 
a large number of cars of all types is that 
known as the roller. This form is made in three 
distinct types, one of which is known as the 
taper roller, another one the solid straight 
roller, and the third one the flexible roller. 

The taper roller bearing, Fig. 46, is composed 
of an inner and outer race, the inner race being 



Taper Roller Bearing 

designed to fit over the shaft and the outer one 
being carried by the bearing housing. The 
outer surface of the inner race is conical in 
form and the inner surface of the outer race is 
of a form to correspond, that is, its internal 
diameter is smaller at one side than at the 
other. Between the two races is carried a series 
of steel rolls, each one of which is tapered so 
that it fits between, and bears along its entire 
length on both races. This forms a bearing of 
anti-friction qualities similar to the annular 
ball, with the exception that the contact be¬ 
tween the. rolling members and their supports 



122 


The Automobile Handbook 



Hyatt Self-Oiling Self-Contained Roller Bearin' 




The Automobile Handbook 


123 


is a line rather than a point. It is customary 
to maintain a predetermined distance between 
the separate rolls by providing cages into 
which the rolls fit loosely. It will be seen that 
because of the tapered formation it would be 
impossible to press the inner race hard enough 
to cause it to pass completely through the outer 
race with the rolls in place, while in the other 
direction the inner race would drop out because 
of its own weight. This feature allows the 
tapered roller bearing to withstand a large 
amount of end thrust when this thrust is ap¬ 
plied on one side of the bearing only. 



Fig. 47 

Straight Solid Roller Bearing 

Roller bearings are made of an inner and 
outer race with both surfaces of each race truly 
cylindrical, Fig. 47, and between these races is 
carried a series of straight cylindrical rolls. 
With plain rolls in use, the bearing will not 
withstand any end thrust because of the fact 
that the races and rollers will move freely over 



124 


The Automobile Handbook 


each other in the direction of their axes. When 
it is desired to have this type of bearing with¬ 
stand a thrust load, one or both of the races 
must be made with either a ridge or a groove 
at or near one edge and the rolls must then 
have a corresponding ridge or groove to en¬ 
gage the race. 

The flexible roller bearing is made by the 
Hyatt Roller Bearing Co. and consists of two 
races, each of which is tubular or cylindrical 
in form, and between these races is carried a 
series of rollers, as in other types previously 
described, differing in that the rolls are formed 
from a piece of comparatively thin flat steel 
twisted into a spiral. It is from the springiness 
of this form of spiral roller that the bearing 
takes its name, “ Flexible/ ’ 


The Automobile Handbook 


125 


Bendix Drive. The Bendix drive, Fig. 49, 
consists of a solid or hollow shaft having screw 
threads on the outside, and a hollow gear hav¬ 
ing screw threads on the inside, so that the 
gear screws on the shaft like a nut on a bolt. 
A circular weight is fastened to the gear, and 
is slightly out of balance. A coil spring con¬ 
nects the electric motor shaft and the hollow 
screw shaft. 



Fig. 49 

Starting Motor With Bendix Drive 
When the electric motor starts it drives 
through the spring and turns the screw shaft. 
Because of the weight, the gear is too heavy to 
turn with the screw shaft, and because the 
gear does not turn it must move along the 
screw shaft (just the same as if you turned a 
bolt having a nut on it, and kept holding the 
nut with your fingers to keep it from turning 
so that it would be screwed along the bolt). 
After the screw gear has moved along the 
screw shaft and engages with the flywheel gear 
it then keeps on moving along until it reaches 




126 The Automobile Handbook 

the stop at the end of the screw shaft. The 
two gears then are fully meshed, and it is obvi¬ 
ous that when the screw gear has reached the 
stop it cannot move any farther, and it then 
must turn with the screw shaft. At this par¬ 
ticular moment the screw shaft and electric 
motor are revolving at a great speed, and this 
great blow and the power of the electric- motor 
are both taken through the coil spring. The 
spring keeps coiling until all this power has 
been applied to the flywheel gear and the en¬ 
gine starts turning. 

As soon as the engine starts exploding and 
runs under its own power, the flywheel of 
course turns much faster than it was cranked 
by the starter. Because it is now turning so 
much faster it increases the speed of the screw 
gear so that the latter runs faster than the 
screw shaft on which it is mounted. It is there¬ 
fore plain that if the screw gear runs faster 
than the screw shaft, that it will be screwed 
on the threads of the shaft (like a nut on a bolt) 
until it has been screwed out of mesh with the 
flywheel gear. This demeshing movement is 
entirely automatic and eliminates the use of 
an overrunning clutch. And now that the 
screw gear is out of mesh it is natural to sup¬ 
pose if the electric motor keeps running that 
the gear will be automatically screwed right 
back into the mesh with the flywheel gear. But 
the unbalanced weight on the screw gear per- 


The Automobile Handbook 127 


forms its automatic function. That is, being 
slightly out of balance, the weight twists or 
cocks the screw gear so that it clutches and 
binds on the screw shaft and turns with it. This 
automatic clutching is all due to the centrifugal 
force of the unbalanced weight. 

When the electric motor stops running, the 
screw gear has been fully screwed away from 
the flywheel gear, and it remains in that re¬ 
tarded position until it is again required to 
start the engine. 

The screw shaft should never be oiled or 
lubricated. It is not necessary and, in fact, 
the screw gear works to the best advantage 
when the screw shaft is dry. 

Through accident or otherwise, should the 
flywheel ever be entirely exposed and unpro¬ 
tected, and should the gear tend to stick on 
the shaft, it may then be necessary to clean 
the screw. 

The teeth on the screw gear and flywheel are 
chamfered or pointed on only one side to make 
the meshing natural and easy. However, should 
the teeth meet, end to end, the screw shaft 
itself is designed to move automatically back¬ 
wards, against and compress the coil spring. 
This gives the screw gear time enough to turn 
and enter the flywheel gear. Should sticking 
of gears ever occur, they can be released by 
throwing in the clutch and moving the car. 
Such trouble would be due to incorrect cham- 


128 The Automobile Handbook 


fering or inaccurate alignment of tlie gears. 
Also it might be due to the binding of the drive 
parts and prevent compressing and proper func¬ 
tioning. Such defects should be corrected. 

If while the engine is running, the electric 
motor should be accidentally started, the screw 
gear will of course screw over against the turn¬ 
ing flywheel gear. But instead of the clashing 
and smashing of gears that might be expected 
there is no damage whatsoever, as the gears 
simply touch once. This is because the flywheel 
gear will speed up the screw gear, and thus 
automatically screw it away. The turning screw 
gear will then automatically clutch and bind 
on the screw shaft, in exactly the same manner 
as when it is cranking and has been demeshed 
when the engine starts exploding. 

Bodies. In the construction of automobile 
bodies the sills are made strong, and the super-' 
work is rendered independent of the actual 
structural strains. Wood is generally used in 
the framing, although it is sometimes replaced 
by cast aluminum. 

When wood is used for framing, sheet alumi¬ 
nium, steel and thin layers of wood are em¬ 
ployed. The aluminum is laid on a form and 
beaten to the shape required for the panel. The 
steel sheets are die formed, while the wood is 
made flexible in order that it may be bent to 
its proper shape when fastened to the body. In 
order to have the car of light weight, all body 
builders use the lightest materials possible in 


The Automobile Handbook 


129 


the construction of that portion which lies above 
the chassis. 

When aluminum is used in the panels and 
for facings, care must be exercised to prevent 
water from creeping in between the metal and 
the framing, because water causes an electro¬ 
lytic action on the aluminum plates. To prevent 
the oxidation of sheet steel, the plates are either 
coated with aluminum or zinc, or they are given 
a priming coat of paint on the inside. 

As a general thing, putty is not used in the 
construction of bodies, as there are few joints 
which require it. In the very best body paint¬ 
ing twenty coats are used before the paint as¬ 
sumes its proper finish. The first coat, or prim¬ 
ing coat, generally consists of pure white lead 
mixed in oil. After that the second priming coat 
is given to it, and from then on the number 
of coats of rough paint will depend upon the 
nature of the surface and the degree of finish. 
For a very fine finish, the last coats consist of 
varnish, but when wagon finish is desired, the 
last coats consist of paint. 

Finishers must take into account the fact that 
all cars are more or less abused in service, and 
it is to be expected that the magnificently 
equipped limousine will have a somewhat finer 
finish than the hard used touring car. 

Classification of Bodies. Besides being 
classified according to the type of gasoline en¬ 
gine, methods of transmission, number of cyl¬ 
inders, etc., automobiles are also classified ac- 


130 The Automobile Hmdbooh 

cording to the type of body which is mounted 
on the chassis. While there are a considerable 
number of names which are given to the same 
types of pleasure automobiles, they may be gen¬ 
erally classified as runabouts, roadsters, toura- 
bouts, touring cars, town cars or taxicabs, lan- 
daulets, limousines and semi-limousines. Elec¬ 
tric automobiles are generally divided into 
coupes, brougham, stanhopes, runabouts, phae¬ 
tons, etc. Steam cars follow the same genera) 
classification as gasoline machines. Commer¬ 
cial vehicles may be classified as taxicabs, deliv¬ 
ery wagons, trucks, busses, wagonettes, ambu¬ 
lances, patrol wagons and other forms for fire 
service. 

Commercial Vehicles. In the commercial 
vehicle field steam, electric and gasoline ma¬ 
chines are used. Electric vehicles are used for 
certain purposes, from heavy trucks to light 
delivery wagons, usually only for short dis¬ 
tances. Steam power is not at present being 
used to any extent for heavy trucks, while 
the gasoline commercial is used for trucks, 
business wagons and quick deliveries. 

The commercial vehicle may be classed as 
follows: Taxicabs, general delivery, light trucks, 
heavy trucks, coal wagons, sight-seeing cars, 
busses, ambulances and particular other types 
for special purposes. 

Since, for general purposes, the speed of com¬ 
mercial vehicles is small, they are not neces¬ 
sarily equipped with high power, as a heavy 


The Automobile Handbook 


131 


car, which would travel at a high speed, would 
be apt to be dangerous. The speeds obtainable 
range on an average between twenty miles per 
hour for delivery wagons, to five miles per hour 
for heavy trucks. 

While there are many distinct types of car 
bodies, there are more names in use than there 
are bodies, because different makers often apply 
different names to the same type of body, and 
often list a certain type of body under a name 
different from the one ordinarily accepted. This 
practice makes it difficult to state positively that 
a certain type of body will be called by a given 
name by a maker although that particular body 
is of its own distinctive type regardless of the 
name applied in the catalogues. 

Bodies may be classified according to the num¬ 
ber of persons carried, whether they are wholly 
or partly enclosed and according to the purpose 



Fig. 50 

Five-Passenger Touring Car 
for which they are designed. None of these 
divisions is very satisfactory, because some types 




132 


The Automobile Handbook 


would appear in more than one division. The 
following definitions are those generally ac¬ 
cepted. 

Touring Car. This is an open car, Figs. 50 
and 51, for general purposes which may seat 
four, five, six or seven persons, including the 
driver. It has sides and doors, but when pro¬ 
tection from the weather is desired the operator 
uses a folding top and curtains. 



Fig. 51 

Seating Arrangement in Four-Passenger Car 

A touring car seating five is called a five-pas¬ 
senger touring car, one seating seven is called a 
seven-passenger touring car, and so on for any 
number of passengers. The rear compartment of 
a touring car is called a tonneau, the front com¬ 
partment is called the driver’s compartment. 

Close-Coupled or Toy Tonneau. A four- 
passenger touring car with the rear seat brought 
well forward is sometimes called by one of these 
names. 

Torpedo. This is a touring car having the 
body as small and low as possible while seating 







The Automobile Handbook 


133 


the number of passengers desired. The body is 
of a form that offers the least resistance to wind 
pressure and is called “stream line” in shape. 

Runabout. This is an open body seating two 
passengers, mounted on a comparatively small, 
light or low powered chassis for use in town and 
city travel and short country trips. 



Fig. 52 

Two-Passenger Roadster 

/• Roadster. This is also an open body, Fig. 52, 
seating two passengers, but mounted on a chassis 
whose size, weight and power fits it for heavy 
work and long distance touring. 

Speedster or Raceabout. This is a powerful 
chassis carrying small, light seats for two pas¬ 
sengers and designed for high speed work. The 
body is made as small and light as possible with 
“bucket” seats, floor, dash, gasoline and oil 
tanks, but no sides or doors, and in most cases 
without a top. 

Limousine. This is a type of body, Fig. 53, 
used mostly for town and city driving in bad 
weather or during the cold season. 




134 The Automobile Handbook 

It seats four, five, six or seven persons in addi¬ 
tion to the driver. It has a permanent top and 
the rear compartment is entirely enclosed and 
has full doors. The driver’s compartment is di- 



Fig. 53 

Limousine Body 


vided from the rear by a partition and this com¬ 
partment is only partly enclosed. 

Berline or Berlin. This type is exactly like 
the limousine except that the driver’s compart¬ 
ment is fully enclosed and has full doors. 

Sedan. This body is like the Berline, that is 
to say, fully enclosed, but there is no partition 
between the driver’s and rear compartment. 

Landaulet or Landau. This is a limousine 
which has the rear half of the passenger com¬ 
partment closed with a top that is rigid when 
raised but that lets down like those tops of closed 
carriages in common use. 









The Automobile Handbook 135 

Town Car. This type has the rear compart¬ 
ment entirely enclosed with full doors, and seats 
four or five persons in this part of the car. The 
driver’s compartment is open, the same as in a 
touring car. The driver may be protected by a 
small canopy extending forward from the en¬ 
closed portion. 



Fig. 54 
Coupe 

Coupe. This type of body, Fig. 54, is entirely 
enclosed and has full doors. It may seat two, 
three or four passengers in the enclosed part, 
the driver being one of these. It is mounted on 
a roadster chassis and bears the same relation to 
the roadster that the Sedan bears to the touring 
car. 

Convertible Coupe or Sedan. These bodies 
are built in such a way that they give exactly 
the same appearance as a regular Coupe or Sedan 
from either the outside or inside. The upper 











136 


The Automobile Handbook 


portion is removable so that the Coupe or Sedan 
is converted into a roadster or touring car, de¬ 
pending on the arrangement and number of 
passengers carried. 

Cabriolet or Couplet. A convertible coupe 
may be called by either one of these names, both 
meaning the same thing. 

Taxicab. A car used as a public vehicle and 
being for hire according to certain designated 
rates of fare is called a taxicab. It is fitted with 
a “taximeter” which records the distance trav¬ 
eled and the time spent in waiting, and automat- 
ally computes and indicates the fare to be paid. 

Taxicabs may be made from limousines, lan- 
daulets or town cars, the landaulet being the 
type most generally used. 

Commercial Car Bodies. These types include 
those used for carrying merchandise and also 
those used for carrying passengers as a business. 
Commercial car bodies may be designated accord¬ 
ing to the type of construction, the class of work 
to be handled or the weight to be carried. 

Truck Bodies. These include the express, 
platform, stake and panel types, and also many 
special designs. Truck bodies are usually made 
from designs prepared for each individual job 
and according to the customer’s requirements, 
except in the lower priced cars. 

Passenger Bodies. These include taxicabs, 
sight seeing cars, carrying from eight to twenty 
persons, and closed bodies suitable for carrying 
passengers and baggage in interurban work. 


The Automobile Handbook 


137 



a necessarv Dart of the machinery of an auto¬ 
mobile and enables the operator by exerting a 
slight amount of force on a lever to reduce the 

























138 The Automobile Handbook 

momentum of the moving car. Brakes used on 
automobiles may be divided into three classes: 
Hub or rear wheel brakes, transmission and 
differential gear brakes. Brakes have also been 
applied to the tires of the rear wheels, but 
have proved unsatisfactory and have been aban¬ 
doned. The forms of brakes in use are single, 
or double-acting, foot or hand operated, and of 
the band, block or expanding ring types. 

Figure 55, at A, B and C, shows three forms 
of the simplest type of single-acting band-brake. 
This type of brake can only be operated success¬ 
fully with the brake wheel running in one 
direction only, which is indicated by the arrows 
in the drawing. If the brakes be operated in 
the reverse direction to that indicated by the 
arrows the result will be to jerk the lever or 
pedal out of the control of the operator of the 
car. 

The three forms of band-brakes shown at A, 
B and C are all of the same principle, the differ¬ 
ence being in the location of the fixed end of 
the brake-band and the shape of the operating 
lever. Type D is a form of double acting block- 
brake, which is designed with a view to elimi¬ 
nate any strain or side thrust upon the shaft of 
the brake wheel which may be caused by the 
braking action of the device. Types E, G and 
H are three types of double acting band-brakes, 
in which the brake may be applied with the 
brake wheel running in either direction. 

Type F is a form of double acting block-brake, 


The Automobile Handbook 139 

in which the right hand ends of the brake-shoe 
arms are pivoted to stationary supports, and 
the left hand ends connected together by means 
of a link and bell-crank lever as shown in the 
drawing. 



In Figure 56 a form of double acting block- 
brake I is shown, which is extremely powerful 
on account of its peculiar construction, in that 
is has a double leverage upon the brake wheel, 
which may be readily seen by reference to the 
drawing. Types J and K are of the form known 




















140 


The Automobile Handbook 


as internal brakes and of the expanding ring 
type, the brakes operating upon the inner sur¬ 
face or periphery of the brake wheel, instead 
of the outside. They are known as hub brakes, 
being usually attached to the hubs of the rear 
wheels of the car. Type L shows a form of 
block-brake in which the pivoted brake arms 
are drawn together by the eccentric located on 
the brake lever shaft. When the lever is re- 



Fig. 57 


leased the brake-shoe arms are forced apart by 
the action of the coil spring between the upper 
ends of the arms. 

Expanding Brake. In the internally expand¬ 
ing brake, Figure 57, a hollow metal drum or 
pulley D is carried upon some continuously 
revolving portion of the car mechanism, and 
within this drum are supported two metallic 
shoes B B, which conform in shape to the inside 




The Automobile Handbook 


141 


surface of the drum by means of a spring, S S. 
The shoes are capable of being strongly pressed 
against the revolving inner surface of the drum 
by means of a cam or toggle arrangement, T, 
operated through a wire rope or metal rod, R, 
from the operator’s lever or pedal. It is im¬ 
portant that brakes of both these types should 
have their bands or shoes so arranged that an 
equal frictional effect is produced upon their 
drums for a given force applied by the operator, 



whether the vehicle is running forward or back¬ 
ward. A brake so arranged is said to be double 
acting. Another type of expanding brake is 
shown in Figure 58, where D is the brake drum; 
S S, the brake shoes; T, the toggle arrangement 
which connects with the brake lever, and N is 
a nut which is used for adjusting the movement 
of the brake shoes. 

Advantages of the Expanding Brake. The 
expanding brake is coming more and more 



142 The Automobile Handbook 

into general use, and is taking the place of 
the contracting brake in many cases, although 
the latter is still being used extensively as an 
emergency brake. 

The advantages of the expanding brake are: 
(1) it is less liable to drag upon the drum; (2) 
it is easily made double acting; (3) it has more 
braking power for a given pressure; (4) the 
friction surfaces are better protected from mud 
and grit. 

A form of brake designed for heavy service is 
that known as the “hydraulic,” in which the 
braking force is carried by means of oil through 
suitable piping from a compressing cylinder to 
a working cylinder. The lever operated by the 
driver is located in the usual place and is con¬ 
nected to the piston of a powerful oil pump. 
From this pump connections lead to a similar 
cylinder on the chassis and from the piston and 
plunger of this second cylinder connection is 
made with the usual forms of brake mechanism. 
The pump is operated by successive strokes of 
the lever that increase the pressure; while the 
brakes are released by pressing a button that 
opens a valve and by releasing the hand lever. 

Brake Linings. For expanding brakes, metal 
shoes have become standard, owing to the prac¬ 
ticability of maintaining proper lubrication be¬ 
tween the frictional surfaces. In external 
brakes the metal band is provided with some 
form of nonmetallic lining that forms the brak¬ 
ing surface applied to the drum. The reason 


The Automobile Handbook 


143 


for this is that it is practically impossible to 
properly lubricate an external brake. Various 
kinds of material, viz., leather fabric, asbestos, 
vulcanized fibre and camel’s hair belting, are 
used for lining external brake bands. A ma¬ 
terial which is used for this purpose must have 
great resisting powers, a constant co-efficient 
of friction, even in the presence of oil and 
water, and it must have the ability to resist 
the influence of heat due to the brake’s action. 
In practice it has been found that leather lined 
brakes burn out, and fibre linings become brittle 
and cannot be depended upon, so that inorganic 
materials, which cannot be carbonized, such as 
asbestos fibre, are widely used. Asbestos fibre 
may be readily woven into a fabric which an¬ 
swers this requirement, but when used by itself 
its strength is not sufficient. When, however, 
it is woven over a metal wire gauze foundation 
it appears to have the necessary stability to 
withstand very severe service, and this is the 
method employed in manufacturing the incom¬ 
bustible brake linings which are being used. 

Cork is the bark of the cork tree, and is the 
lightest known solid. Its weight is one-eleventh 
of aluminum, and one-thirtieth of cast-iron. It 
hajs a very high co-efficient of friction, and is 
not affected by many of the conditions which 
seriously impair the efficiency of other sub¬ 
stances. 

Cork possesses qualities which distinguish it 
from all other solids, namely, its power of alter- 


144 


The Automobile Handbook 


ing its volume to a very marked degree in con¬ 
sequence of a change of pressure. It consists, 
practically of an aggregation of minute air ves¬ 
sels, having thin, water-tight, and very strong 
walls, hence, if compressed, the resistance to 
compression rises in a manner more like the re¬ 
sistance of a gas, for instance, than to that of 
an elastic solid, such as a spring. The elasticity 
of cork has a wide range and is very persistent. 
It is this elasticity which makes it valuable when 
used as an insert in a metal shoe. Cork is of 
rather a brittle nature, though extremely strong, 
and for that reason it cannot be used in the form 
of a lining or facing. The method of appli¬ 
cation is to insert corks in holes in the brake 
provided for the purpose. Cork is not particu¬ 
larly affected by heat or oil, and will largely in¬ 
crease the efficiency in any application to a 
brake or clutch. 

Where metal-to-metal surfaces, with or with¬ 
out cork inserts, are used, the surfaces are usu¬ 
ally of different materials. The most common 
material for drums in all cases is steel, but that 
of shoes is either malleable cast iron, brass or a 
bronze. Different metals make a better wear¬ 
ing surface, and some combinations will have a 
higher degree of friction adhesion than others. 

In the selection of material for brake linings, 
the co-efficient of friction is an important factor 
to be considered. Table 7 gives the relative 
values existing in combinations of different 
materials. 


The Automobile Handbook 


145 


TABLE 7. 


Material— 
Metal to Wood . 
Metal to Fibre . . 
Metal to Leather 
Metal to Metal . 
Metal to Cork . . 


Co-efficient 
of friction 
0.25 to 0.50 
0.27 to 0.00 
0.30 to 0.60 
0.15 to 0.30 
0.36 to 0.65 


Equalizers. In connection with all brakes 
which are used in pairs, some method is used to 
equalize the pressure of the brake handle or foot 
pedal so that the same pressure will be applied 



to both brakes. If the power is not equally ap¬ 
plied to each brake, side slip or “skidding” will 
result. 

The different methods of equalizing brakes are 
shown in Figs. 59, 60, 61 and 62, the majority of 
cars using what is known as the floating lever 
type, the cable arrangement being used only on 
several makes of cars. The floating lever type 


































14G 


The Automobile Handbook 


of equalizer is illustrated in Fig. 59. L is the 
floating lever, connected at its central point to 
the brake lever, or pedal by means of rod R. 
The ends of lever L are connected to the brakes 
B, B, by means of the brake rods C and D. 
When rod R is drawn forward, lever L draws 
rods C and D forward thus giving an equal pres¬ 
sure on the hub brakes. 

Fig. 60 shows another type of floating lever 
equalizer. Shaft S connects to the brakes by 



means of rocker arms located just outside the 
frame. Two rocker arms, C and D are con¬ 
nected to shaft S, and to the equalizing lever L 
by means of rods E and F. In some cases the 
equalizing lever is located outside of the frame. 
It then takes the form shown in Fig. 61, in 
which L is the lever that equalizes the pressure 
on both brakes connected to shaft S. Fig. 62 
shows the arrangement of the cord equalizer. 
Shaft S is connected to the two brakes, one at 











The Automobile Handbook 147 

each end, and it has two rockers, or cranks E 
and F attached to it. Parallel to S is another 
shaft C, which carries a grooved roller R. A 
cable is connected to crank E, carried over R, 
and then passing back, is connected to crank F. 
When R is moved in the direction of the arrow, 
by the brake lever, the cord distributes the ten¬ 
sion between E and F, and as a consequence the 
brake also. This type is much cheaper than 



Fig. 61 

pi Equalizer Lever Outside the Frame 


































148 The Automobile Handbook 

Brazing. Many workmen labor under the im¬ 
pression that a brazing job cannot be done un¬ 
less the parts are a loose fit, in order, as they 
say, to allow the brazing material to enter and 
form a bond. The result is, when they do the 
work, the parts are a very loose fit, with accen¬ 
tuated shearing tendencies in the section of the 
bra dng material, and if the brazing happens to 
be poorly done, the result is anything but good, 
since, in the absence of brazing, there is not 
even a good mechanical bond. 

A good mechanical bond is possible to procure 
without, in any way, interfering with the braz¬ 
ing process, since the parts, if they are well 
fluxed, will take a coat of brazing material, even 
when the recess is but a thousandth or two. In 
brazing, if the work is to be up to a sufficient 
standard to use in steering gear, it is necessary 
to clean and brighten the surfaces in a most 
thorough manner. This will best follow by me¬ 
chanical scraping rather than by dipping in 
some corroding material. Dipping may be of 
value as a preliminary, but a file, and scraper, 
in the hands of a man of competence, w r ill go a 
long ways toward success. 

When the parts are well brightened, and the 
grease is thoroughly removed, by the use of 
soda water, benzine, or equally good solvents, 
it remains to flux the parts with borax, and 
then apply the heat, either by a forge or from a 
special form of brazing torch which uses gaso¬ 
line, kerosene, or other fuel oil, to pro¬ 
duce the necessary heat. All forms of burn- 


The Automobile Handbook 149 

ers have means of adjusting the flame, and 
two or more burners are usually placed 
in such position that their flames strike 
the work. Torches are similar to the 
Bunsen burner; if fire brick, or clay, is used to 
build up around the parts, the heating process 
will be attended with less difficulty, and the work 
will be better at the finish. A rather hard braz¬ 
ing material may be used. This may be pur¬ 
chased ready for use, and there is no reason at 
all why a motorist of even slight skill cannot 
make a good job of brazing. 

Camshaft. Fig. 63 is a sectional view of a mo¬ 
tor cylinder and illustrates the principle and ac¬ 
tion of the camshaft. In many motors one cam¬ 
shaft serves to open both intake and exhaust 
valves, while in other motors there is a cam-shaft 
for each set of valves. Besides opening the valves, 
the cams determine the length of time the valves 
remain open, also the speed with which it opens 
and closes. Referring to Fig. 63, A is the crank¬ 
shaft, P the piston, D is the cam-shaft which 
carries the cam E. The speed of the cam-shaft 
depends upon the type of engine. The one 
shown in Fig. 63 is driven at half the speed of 
the crank-shaft through the gear wheels B and 
C, B being one half the size of C. H is the 
valve to be opened, which in opening must be 
lifted off its seat. This is done when the cam 
E revolves and raises the roller G on the lower 
end of lifter rod F which extends upward rest¬ 
ing against the lower end of the stem of valve 


150 


The Automobile Handbook 


H, although between the two rods, or rather at 
their point of contact are nut and lock-nut L, 



Fig. 63 

A Camshaft and Its Location 


for adjusting the length of F when timing the 
valve. K is a spiral spring, the function of 







The Automobile Handbook 151 

which is to close the valve, after the cam E trav¬ 
els around and allows G to drop. Directly 
above valve H is the intake valve M, which in 
this case opens downward. This valve opens 
automatically, due to the suction of the piston 
in moving downwards on the intake stroke, but 
is kept closed during the compression and ex¬ 
haust strokes of the piston, by the pressure in 
the cylinder. 

Modern forms of construction make the cam¬ 
shaft and cams from one piece of steel, and the 
cams are then said to be integral with the shaft. 
This method makes it possible to place the cams 
in exactly the right position at the factory, and 
the danger of lost power from improper placing 
is thus greatly reduced. 

Carbon Deposit—Symptoms of. One of the 
most fruitful sources of trouble in internal com¬ 
bustion motors is that of the carbon deposit. If 
the cylinders get too much oil, or if oil of a 
heavy or inferior grade is used, a portion of it 
will work up past the pistons, where it will be 
evaporated or consumed by the intense heat, 
leaving a deposit of carbon. This may be aug¬ 
mented by too rich a mixture, which serves to 
deposit film upon film of carbon on the inside, 
and top of the compression chamber, and on the 
head of the piston. The films thus formed will 
in time commence to scale, and the projections 
fused by the heat of the explosions will serve to 
prematurely ignite the charge. The symptoms 
are back-firing and knocking in the cylinders 


152 The Automobile Handbook 

—as if the spark were too far advanced. An 
almost infallible symptom of excessive carbon 
deposit in the cylinders is the motor showing 
plenty of power at high car speeds, but deficient 
in hill-climbing on high gear. At slow engine 
speeds the incandescent carbon projections serve 
to pre-ignite the charge, thereby reducing the 
power of the motor. The cure is to take off the 
cylinder head and scrape olf the carbon deposit 
from the top of the piston and inside of the cyl¬ 
inder head. Carbon also will form on the porce¬ 
lain portion of the spark plugs, thereby furnish¬ 
ing a circuit which the high tension current may 
follow, rather than jump the gap between the 
points of the plug. Usually only a part of the 
current will pass by way of the carbon film, 
still leaving a weak spark at the points, which 
in open air, when testing plugs, may seem strong 
enough. This causes intermittent firing. The 
symptoms are similar to a poor contact com¬ 
mutator. This condition is difficult to detect, 
for the reason that when the plug is subjected 
to the usual test of removing from the cylinder 
and closing the electrical circuit, the spark is 
seen to jump free and fat between the sparking 
points. This is because electrical energy which 
is sufficient to jump between two points %-inch 
apart in the open air will jump less than 1/16- 
inch in the explosion chamber under 60 pounds 
compression. The causes of overheating in 
motors may be summed up as follows: Poor oil, 
insufficient oil, bad mixture, slow spark, ob- 


The Automobile Handbook 


153 


structed water pipe, low water and valves out 
of time. 

Lubricating oil is charged with the crime of 
depositing carbon on the surfaces of the com¬ 
bustion chamber, and this carbon in turn causes 
“bucking,” and pre-ignition. It probably is true 
that inferior cylinder lubricating oil will de¬ 
posit carbon, to some extent, but the main trou¬ 
ble is from the gasoline which will not vaporize 
until it is allowed to contact with the hot cyl¬ 
inder walls, and this process of reducing the 
gasoline to vapor is bound to lead to a carbon 
deposit for the same reason that wood is 
“coked” if it is heated to a temperature of 
about 650 deg. C., provided the amount of air 
present is less than that which would cause 
complete combustion. 


154 


The Automobile Handbook 


Carburetors, Principles of. Internal combus¬ 
tion engines used for the propulsion of motor 
cars use gasoline for fuel in almost all cases. 
Experimenting is now going on in the endeavor 
to use kerosene or alcohol, and in some cases 
even lower grades of fuel. Gasoline and kero¬ 
sene are secured by heating crude petroleum 
until vapor is given off, and this vapor is passed 
through pipes that are kept cool enough to con¬ 
dense the vapor into a liquid. Alcohol is se¬ 
cured by the distillation of fermented vege¬ 
table matter, and may be secured in almost 
any part of the country if suitable means for 
distillation were to be developed. 

Before the gasoline is ready to burn in the 
engine cylinders, it must be turned into a gas 
or vapor. If gasoline stands exposed to the air 
it will vaporize at a comparatively slow rate, 
but if ejected from a small opening in a fine 
stream it will turn to vapor and mix with air 
much more rapidly. It is always necessary to 
mix the gasoline vapor with air in certain pro¬ 
portions to make a combustible mixture. The 
instrument that turns the gasoline into a gas 
and then mixes the gas with air is called the 
carburetor and the process is called carbureting. 

Many forms of carburetors have been made 
and used, but all instruments now fitted are of 
the type known as automatic float feed. The 
spray nozzle is the small opening inside of the 
carburetor through which the liquid gasoline 
is drawn when it is to be made into a vapor. 


The Automobile Handbook 


155 


The nozzle opening is placed in a tube through 
which the air must pass on its way to the engine 
cylinders. See Fig. 64. One end of this tube 
is open to the outside air and the other end 
attaches to the piping that goes to the engine 
cylinders. The end open to the air is called 
the primary air intake. 



Fig. 64 

Float-Feed Carburetor Mixing Chamber and Air 
Valve. A, Spray Nozzle. B, Adjusting Needle 
Valve. C, Primary Air Intake. D, Auxiliary Air 
Valve. E, Air Valve Spring. F, Throttle Valve. 

When the piston travels away from the cylin¬ 
der head on the inlet stroke, the inlet valve 
opens and a cylinder full of mixture is drawn 
from the carburetor. The air to make the mix- 






156 


The Automobile Handbook 


ture is drawn through the carburetor primary 
air intake and must pass by the nozzle opening. 
The gasoline is maintained at a height slightly 
below the nozzle opening, and the suction, or 
partial vacuum, of the incoming air causes 
some of the gasoline to be drawn out of the 
nozzle so that its spray mixes with the air. 
This is the principle on which all modern car¬ 
buretors operate, but certain added features 
are necessary to compensate for the different 
conditions obtaining under different rates of 
car speed and engine load. 

The first difficulty that would be encountered 
with the simple form of carburetor just de¬ 
scribed would be that of a falling gasoline 
level in the nozzle as the fuel was drawn into 
the engine. This would finally result in a fail¬ 
ure of the fuel supply and stoppage of the 
engine. In actual practice, the gasoline from 
the car’s tank does not pass directly into the 
nozzle, but goes first into a small tank on the 
carburetor, which tank is called the float cham¬ 
ber. Of the two openings in this small tank, 
one goes to the gasoline supply and the other 
communicates with the carburetor nozzle. In¬ 
side of the float chamber is a piece of cork cov¬ 
ered with shellac or else a hollow metal cylin¬ 
der, either of which will float on the surface of 
whatever gasoline may be in the chamber. At 
the opening of the pipe that comes into the 
float chamber from the gasoline tank is a small 
valve, Fig. 65, operated by connections at- 


The Automobile Handbook 


157 


tached to the float itself. When the float is 
low down in the chamber this valve is open; 
bat as the float rises on the surface of the liquid 
coming from the tank, it finally reaches a height 



Fig. 65 


Carburetor Float Valve Mechanism. A, Float. B, 
Float Lever Pivot. C, Float Lever. D, Float 
Valve. E, Gasoline Inlet, 
at which the valve is closed, and it will there¬ 
fore be seen that the level of the liquid cannot 
rise above the point determined by the position 
of the float when the valve closes. When gaso¬ 
line is drawn from the float chamber, through 
the nozzle, the float falls with the fuel level 
until the valve is again opened, and by this 
repeated action the level is maintained constant. 

Other parts of the carburetor, such as the 
auxiliary air valve, are described in the follow¬ 
ing pages and the construction and adjustment 
of the well known makes are taken up. 











158 The Automobile Handbook 

Almost any carburetor will give a reasonably 
good mixture through a limited range of action. 
Frequently, however, this range is found insuf¬ 
ficient for a particular engine. If right for low 
speeds, it is wrong for high speeds, and vice 
versa. 

The theory of carburetor action as regards 
the behavior of the gasoline jet under different 
air velocities is still only partially understood, 
and has been the subject of a great deal of 
more or less blind theorizing, based in many 
cases on wholly inadequate data. 

A non-automatic spraying carburetor (i. e., a 
simple nozzle in an air tube) makes no mixture 
at all till the velocity of the air stream reaches 
a certain minimum. Beyond this point, the 
richness increases with the speed. Dilution 
from the auxiliary valve is therefore required 
only when the richness of the mixture exceeds 
the normal. At this point it should be remem¬ 
bered that, so far as the spray is concerned, 
there is no difference between a wide open throt¬ 
tle at slow engine speed (as for instance, up 
hill) and reduced throttle with high engine 
speed. The spraying action is concerned only 
with the velocity of the air past the nozzle be¬ 
fore the throttle is reached. 

Almost every carburetor is provided with the 
needle valve controlling the spray orifice. With 
this provision it is very easy to determine 
whether or not the carburetor is doing as well 
as it should at either low or high speed. For 


The Automobile Handbook 159 

example, suppose we start with an adjust¬ 
ment known to be satisfactory for medium 
speeds. If the low speed performance is under 
suspicion, it is only necessary to increase the 
needle valve opening slightly to ascertain 
whether starting is thereby made easier, and a 
walking pace more smoothly maintained. If 
overheating results, reducing the needle open¬ 
ing will probably cure it. Similarly slight 
changes in the needle opening, without chang¬ 
ing any other adjustment, will determine 
whether or not the mixture is improved by 
less, or more gasoline at high speed. When the 
carburetor is set for a medium speed, if the mix¬ 
ture is weak at low speeds, and rich at high 
speeds, more air should be admitted, but if the 
mixture is rich at low speeds, and weak at 
high, less air should be admitted. Much de¬ 
pends upon the spring. 

It is a characteristic of all springs that their 
flexure is in direct proportion to the load im¬ 
posed, up to the elastic limit of the spring-. 

The Float Feed Carburetor, Fig. 66, con¬ 
sists of two principal parts: a gasoline recepta¬ 
cle which contains a hollow metal or a cork 
float, suitably arranged to control the supply of 
gasoline from the tank or reservoir, and a tube 
or pipe in which is located a jet or nozzle in 
communication with the gasoline receptacle. 
This tube or pipe is called the mixing chamber. 
The gasoline level is maintained about one-six¬ 
teenth of an inch below the opening in the jet 


The Automobile Handbook 



Fig. 67 

Multiple Spray Carburetor 



























































































The Automobile Handbook 


161 


in the mixing chamber. The inductive action 
of the motor-piston creates a partial vacuum in 
the pipe leading from the mixing chamber of 
the carbureter to the motor, thereby causing 
the gasoline to flow from the jet and mixing 
with the air supply, to be drawn into the cylin¬ 
der of the motor in the form of an explosive 
mixture. 

Spraying Carburetors. In this type of car¬ 
buretor the quantity of gasoline delivered is 
not proportional to the volume of air delivery 
at different rates of flow. This difficulty has, 
however, been met by providing a supplemen¬ 
tary air inlet to the carbureter, which may be 
regulated by the driver at will. 

Another method of correcting the variations 
in the proportions of the gasoline charge is 
shown in Fig. 67, and consists in providing a 
second spray nozzle. In the majority of cases 
in which multiple nozzle carburetors are used, 
there are two nozzles, practically two carbure¬ 
ters, a small one for idle running, and slow 
speeds, and a larger one for heavy work. In 
some instances, three, and even four nozzles are 
used. 

The Venturi Tube Carburetor operates on 
the principle that if two converging air nozzles 
have their small ends brought together, there 
is a point where the suction remains practically 
constant, therefore if the fuel nozzle be located 
at this point the result will be, a constant mix¬ 
ture at all speeds. In a carburetor of this type 


162 


The Automobile Handbook 


there are no auxiliary spring controlled air 
valves, no moving strangling cage, nor any me¬ 
chanical interregulation between the air, and 
the gasoline. 

An elementary Venturi tube is shown in Fig. 
68, which represents the tube A having a head 
of water on it. The discharge at A is greatly 
increased by the addition of the divergent noz¬ 
zle at the outlet end. Under these conditions, 



the velocity of flow in the throat at A is greater 
than that produced by the head H. When a 
pressure gauge is placed at A the pressure is 
found to be less than atmospheric; in fact, the 
fluid is discharging into a partial vacuum, and 
the velocity at A is due to the head H plus the 
head due to the vacuum. Advantage is taken 
of this fact by placing the gasoline outlet at 
the point A, in which case the velocity of the 



























The Automobile Handbook 


163 


suction controls the flow of gasoline at all times 
thus giving a perfect mixture. 

Auxiliary Air-Yalve. It has been deter¬ 
mined from the result of experiments that to 
get the maximum power at any speed from a 
gasoline motor equipped with a float-feed car¬ 
buretor, the jet of the carburetor must have a 
larger opening for low speeds than for high 
speeds. As this practice would require a very 
delicate adjustment it consequently becomes 
almost impracticable, because necessitating a 
constantly varying regulation for each frac¬ 
tional variation of speed of the motor. The 
difficulty may be obviated by the use of an aux¬ 
iliary air-valve, located in the induction-pipe 
close to the inlet-valve of the motor. 

The jet of the carburetor is set for the maxi¬ 
mum quantity of gasoline at the slowest speed 
of the motor, and as the speed is increased the 
auxiliary air-valve comes into action and re¬ 
duces the supply of air passing through the car¬ 
bureter, thereby reducing the suction or partial 
vacuum at this point, and maintaining a con¬ 
stant quality of mixture at all times. 

The auxiliary air valve has been attached to a 
dash pot construction in many makes of modern 
carburetors. The dash pot may operate with 
air or with gasoline for its fluid, but in either 
case the purpose is to prevent sudden opening 
and closing of the valve or “ fluttering/ ’ Such 
fluctuation is a cause of noise and also tends 
to destroy the proportions of the mixture. 


164 


The Automobile Handbook 


Frequently it is observed that the intake to 
the carburetor is so restricted that noise issues, 
and a little further investigation in such cases 
will disclose, in all probability, that wire-draw¬ 
ing is one of the ills. It is not alone the noise 
that is objectionable in such cases; the power 
of the motor will be less, due to the restriction 
which has the effect of reducing the weight of 
mixture that enters into the cylinders, and the 
power of a motor is undoubtedly proportional 
to the weight of mixture that enters the cylin¬ 
ders, assuming, of course, that the same^is in 
acceptable form, and that it is completely 
burned. True, there must be a depression in 
the carburetor in order that there will be a dif¬ 
ference in pressure, so that gasoline will be 
sucked into the train of air; equally true, it is 
of the greatest importance to have the depres¬ 
sion as low as possible in order that the power 
of the motor will be a maximum. If the depres¬ 
sion is but slight, provided the carburetor is 
properly designed, the amount of fuel entrained 
will be adequate for the purpose. If, on the 
other hand, the depression is very large and 
holds considerable fuel, it will soon be found to 
be wasteful of the liquid. 

With the low grades of fuel now in use, wire¬ 
drawing is very harmful, inasmuch as it tends 
to separate the gasoline from the air and causes 
the gasoline vapor to again become a liquid and 
deposit on the tubing walls. 


The Automobile Handbook 


165 


Effect of Cold on Gasoline. The tempera¬ 
ture has a very marked effect on the rapidity 
with which gasoline vaporizes, and in cold 
weather it is necessary to supply heat to the 
carburetor. 

The carburetor should preferably be jacket¬ 
ed, and it may be warmed either from the circu¬ 
lating water, or by taking a small quantity of 
the hot gases from the exhaust pipe. If water is 
used it should be taken from a point just be¬ 
yond the discharge of the pump, and should be 
delivered to the return pipe from the engine 
jacket to the radiator. 

Whether exhaust gases or water is used, the 
flow should be regulated by a cock, otherwise 
too much heat will be received in warm weather. 
When the carburetor is cold, the engine may be 
started by pouring warm water over it, care be¬ 
ing taken not to let any portion of the water 
get into the gasoline through any aperture in 
the top. Another method of warming up the 
carbureter is to wring cloths out of hot water, 
and wrap them around it. 

While it is not generally realized, the flow of 
gasoline through the nozzle is greatly influenced 
by the temperature of the liquid. Gasoline at 
very low temperatures, such as freezing, and 
slightly above, is reduced as much as 30% in 
volume of flow below the point reached when the 
liquid itself is warmed to between 65° and 80° 
Fahrenheit. This forms one more reason for 
jacket heating on all carburetors. 


166 


The Automobile Handbook 


Carburetor Inspection. The float valve of 
the carburetor should be tested for leaks by 
opening the valve between it and the tank and 
looking for gasoline drip. If gasoline escapes, 
it may simply be because the float is set too 
high, so that it does not close the needle valve 
before gasoline issues from the spray nozzle. 
Or, it may be that the valve itself leaks. 

At this stage, it is well to assume that the 
float is properly adjusted, and to begin by shut¬ 
ting off the main gasoline valve, and then un¬ 
screwing the washout plug below the needle 
valve. It may be found that dirt, waste, or a 
splinter of wood has got past the strainer, 
through which, presumably, the gasoline passes 
on its way to the float, and is lodged in the 
needle-valve opening. It may be of advantage 
to open the top of the float chamber, which can 
usually be done without disturbing other parts, 
and take out the float and needle valve. A lit¬ 
tle gasoline washed down through the needle- 
valve orifice will then generally carry away any 
dirt that may have clung to the valve when the 
plug was unscrewed. If the gasoline still drips 
when the parts are reassembled, the mixing 
chamber should be opened and the top of the 
spray nozzle examined to see if gasoline is es¬ 
caping from it. An electric light should be 
used in making an examination of the carbu¬ 
reter, as, with any other illuminant, a fire might 
be started. The portable electric flashlights 
answer the purpose very well. 


The Automobile Handbook 


167 


.Occasionally a carburetor is found to be too 
large for the engine, or to have too large a 
spray orifice. The advice has been given in 
such a case to reduce the size of the spray ori¬ 
fice by lightly pening the top of it with a ham¬ 
mer. This is counsel of doubtful value, even 
if the hole be afterward reamed true, since it is 
manifest that the burr formed in the top of the 
orifice cannot possibly be deep enough to be at 
all regular in its form. It will almost inevita¬ 
bly throw a jet slantwise, instead of straight, 
and this je + failing to strike the main part of 
the air stream will be only partly atomized, 
with resulting misfiring and general bad be¬ 
havior, especially at low speeds. If a new noz¬ 
zle of smaller size cannot be substituted, the 
best thing to do in case there is no needle valve 
to adjust the flow of gasoline to the jet is prob¬ 
ably, to warm the ingoing air as much as possi¬ 
ble, in order to make evaporation by tempera¬ 
ture take the place of atomizing due to the air’s 
velocity. 

Holly Carburetor, Model H. This carbure¬ 
tor is shown in Fig. 69. Before the fuel enters 
the float chamber it passes a strainer disk A 
which removes all foreign matter that might in¬ 
terfere with the seating of the float valve B 
under the action of the cork float and its lever 
C. Fuel passes from the float chamber, D, into 
the nozzle well E, through a passage F, drilled 
through the wall separating them. From the 


168 


The Automobile Handbook 


nozzle well the fuel enters the nozzle proper, G, 
through the hole H, and then rises past the 
needle valve I, to a level in its cup-shaped upper 
end, which just submerges the lower end of a 
small tube, J, which has its outlet at the edge of 
the throttle disk. 



Fig. 69 


Holly Carburetor, Model “H” 

Cranking the engine, with the throttle kept 
nearly closed, causes a very energetic flow of air 
through the tube J and its calibrated throttling 
plug K, but the lower end of this tube is sub¬ 
merged in fuel, with the engine at rest. There- 

































The Automobile Handbook 169 

fore, the act of cranking automatically primes 
the motor. With the motor turning over, under 
its own power, flow through the tube J takes 
place at very high velocity, thus causing the fuel 
entering the tube with the air to be thoroughly 
atomized upon its exit from the small opening 
at the throttle edge. This tube is called the 
“low speed tube” because, for starting and idle 
running, all of the fuel and most of the air in 
the fuel mixture are taken through it. 

As the throttle opening is increased beyond 
that needed by idling of the motor, a consider¬ 
able volume of air is caused to move through the 
passage bounded by the conical walls L of the 
so-called strangling tube. In its passage into 
the strangling tubej the air is made to assume an 
annular, converging-stream form, so that the 
point in its flow at which it attains its highest 
velocity is in the immediate neighborhood of the 
upper end of the “standpipe” M, set on to the 
body of the nozzle piece G. The velocity of ajr 
flow being highest at the upper, or outlet, end of 
the standpipe, the pressure in the air stream 
is lowest at the same point. For this reason 
there is a pressure difference between the top 
and bottom openings of the pipe M, thus causing 
air to flow through it from bottom to top, the air 
passing downward through the series of open¬ 
ings N in the standpipe supporting-bridge and 
then up through the standpipe. 

With a very small throttle opening, the action 
through the standpipe keeps the nozzle thor- 


170 


The Automobile Handbook 


oughly cleaned out, the fuel passing directly 
from the needle opening into the entrance of the 
standpipe. To secure the utmost atomization 
of the fuel, the passage through the standpipe is 
given aspirator form, which further increases 
the velocity of the flow through it, and insures 
the greatest possible mixture of the fuel with the 
air. A further point is that the atomized dis¬ 
charge of the standpipe enters the air stream at 
a point at which the latter attains its highest 
velocity and lowest pressure. 



Fig. 70 

Holly Carburetor, Model “G” 


There is but one adjustment, the needle valve 
I. The effect of a change in its setting is mani¬ 
fest equally over the whole range of the motor. 

Holly Carburetor, Model G. This design is 
especially for Ford cars. Its method of opera- 























The Automobile Handbook 


171 


tion is identical with that of the' Model H, its 
chief differences as compared with the other 
model being structural ones, giving a horizontal 
instead of a vertical outlet, a needle valve con¬ 
trolled from above, and a general condensation 
of the design to secure compactness. 

Fuel enters the carburetor, shown in Fig. 70, 
by way of a float mechanism in which a hinged 
ring float, in rising with the fuel, raises the float 
valve into contact with its seat. The seat is a 
removable piece and the float valve is provided 
with a tip of hard material. 

From the float chamber the gasoline passes 
through the ports E to the nozzle orifice in 
which is located the pointed end of the needle 
F. It is noted that the ports E are well above 
the bottom of the float chamber, so that, even 
should water or other foreign matter enter the 
float chamber it would have to be present in a 
considerable quantity before it could interfere 
with the carburetor operation. 

A drain valve D is provided for the purpose 
of drawing off whatever sediment, or water, may 
accumulate in the float chamber. The float level 
is so set that the gasoline rises past the needle 
valve F and fills the cup G to submerge the 
lower end of the small tube H. Drilled passages 
in the casting communicate with the upper end 
of this tube with an outlet at the edge of the 
throttle disk. The tube and passage give the 
starting and idling actions, as described in con¬ 
nection with the Model H. 


172 


The Automobile Handbook 


The strangling tube I gives the entering air 
stream an annular converging form, in which 
the lowest pressure and highest velocity occur 
immediately above the cup G; thus it is seen that 
the fuel issuing past the needle valve F is imme¬ 
diately picked up by the main air stream at the 
point of the latter’s highest velocity. 

The lever L operates the throttle in the mix¬ 
ture outlet, and a larger disk with its lever S is 
a spring-returned strangler valve in the air in¬ 
take, for facilitating starting in extremely cold 
weather. 


The Automobile Handbook 


173 


Kingston Carburetor. The Kingston carbu¬ 
retor, Fig. 71, uses a ball type of auxiliary 



pKingston Carburetor 


air valve instead of the employment of spring 
control dashpot, diaphragm or auxiliary air 
valve. The main air intake A communicates 
with the vertical mixing chamber B, in which 
the sides C are beveled outward, giving a center 
tube effect, so that the air current converges 
above the nozzle N, as indicated by the arrows. 
D marks the exit to the motor controlled by the 
butterfly throttle E. Auxiliary air enters 
through five circular openings G, arranged in 
a semi-circle in the floor of an extension H of 
the mixing chamber. Each of these five open¬ 
ings consists of a bushing K threaded into the 
opening in the extension H, and having its top 
beveled to receive a five-eighths inch bell metal 
bronze ball L, which is retained in position by 
a threaded bushing M, fitting in the top of the 
extension H. It has a pair of downward project- 


















174 The Automobile Handbook 

ing hooks N for preventing the ball getting out 
of position, but not interfering with the ball 
rising vertically when forced to do so by the 
pull of the motor, at which time additional air 
is admitted. Two others of the five auxiliary 
entrances are shown at I and 0, all of the five 
containing balls of the same size and weight. 
The air entering through the openings guarded 
by these balls has an unrestricted passage into 
the mixing chamber and thence to the motor. 
Any ball is easily moved by unthreading the 
cap M, after which the ball can be lifted out. 

The gasoline enters the carburetor from 
the gasoline tank by way of the connec¬ 
tion J, which is guarded by the needle valve R, 
operated through the lever S, pivoted in the 
side of the casting and with its long arm bear¬ 
ing on the top of the cork float. The float is 
fitted with a metal bushing. Complete control 
of the nozzle N is through the needle valve Y, 
which, at the top of the carbureter, has a T- 
piece X, by which it can be raised or lowered, 
thereby regulating the flow of gasoline. A 
feature of the throttle connection T is the ser¬ 
rated lower face of its hub W, so that by loos¬ 
ening a lock nut Z, the handle T may be turned 
in any direction most convenient. The air in¬ 
take A consists of an L-shaped piece secured 
to the carbureter casting by a nut P, and in the 
base of this is a circle of openings F where cur¬ 
rents of air can enter, the object of these open¬ 
ings being that by priming the carburetor, and 


The Automobile Handbook 175 

overflowing the open mouth of nozzle N the 
gasoline falls to the vicinity of the holes F, and 
the air entering through these openings will 
facilitate the breaking up of the gasoline, and 
thereby assist the starting of the motor. 

Krebs Carburetor. In the Krebs style of car¬ 
buretor, a constant proportion of gasoline and 
air is maintained by means of suitable sections 
of air and gasoline outlets. The openings are 
so arranged that a proper mixture is main¬ 
tained at minimum suctions, after which grad¬ 
ually increasing quantities of supplementary 
air are admitted. 

A number of attempts have been made to im¬ 
prove upon the Krebs principle by variously 
shaping the supplementary air openings, or the 
spring on the supplementary air valves, so as 
to insure complete compensation for the in¬ 
crease in richness of the mixture formed in the 
spray chamber with increasing suction, by the 
addition of the correct amount of supplemen¬ 
tary air at all suctions. The mixture formed in 
an ordinary spray carbureter becomes richer as 
the suction increases. At first the only means 
provided to correct this defect was a hand-regu¬ 
lated air valve; but since the advent of the 
Krebs carbureter, practically all new carburet¬ 
ers brought out have some arrangement for au¬ 
tomatically keeping the mixture constant, re¬ 
gardless of variations in suction. In general 
the means provided are close copies of the 
Krebs supplementary air valve, though in some 


176 


The Automobile Handbook 


instances this valve, instead of being actuated 
by the suction, is operated either hydraulically 
by means of a diaphragm in a chamber commu¬ 
nicating with the water cooling system, or me¬ 
chanically by direct connection with the throt¬ 
tle valve. 


The Automobile Handbook 


177 


Master Carburetor. This carburetor, shown 
in Fig. 72, is unique in that it has no adjust- 



Fig. 72 


Master Carburetor 

ments, and is so simple that it may be readily 
taken apart and put together again. In the 
Master carburetor both the fuel and the air are 
positively regulated. This regulation is accom¬ 
plished by a rotary throttle, which not only un¬ 
covers a series of minute holes in the fuel dis- 



Fig. 73 

Master Carburetor Vaporizing Action 
tributer, but eliminates the butterfly valve found 
in most other carburetors. This action is shown 
in Fig. 73. When the throttle is closed fuel is 












178 


The Automobile Handbook 


admitted through but one hole, sufficient for slow 
speed or idling. As the throttle is opened addi¬ 
tional holes are uncovered, one by one, and the 
fuel supply increased. The rotary valve does not 
become worn, as it does not come in contact with 
the throttle chamber in which it rotates. The 



Fig. 74 

Master Carburetor Damper 


damper shown in Fig. 74 is a rigid plate, extend¬ 
ing entirely across the passageway, paralleling 
the fuel distributer. This damper lever is at¬ 
tached to the hand control located on the steering 
•post by means of a steel wire passing through 
a brass tubing. A trap is located under the float 
chamber and it contains a brass screen that 
filters the fuel, which is again filtered by an¬ 
other screen of tubular form. 

Rayfield Carburetor. The Rayfield carbure¬ 
tor has no direct adjustment for the nozzle 
opening such as would be provided by a screw 
needle valve, but to take the place of such an 
adjustment a type of lever mechanism is used 
that increases or decreases the gasoline supply 




The Automobile Handbook 179 

according to the degree of throttle opening, and 
also provides means for adjusting the fuel flow 
for high or low speeds independently of each 
other. Adjustment is provided through two 
screws with milled heads, one of these serving to 
fix the position of the nozzle adjustment at low 
engine speeds or with a nearly closed throttle 
and the other one operating only when the throt¬ 
tle is more than half way open. The construc¬ 
tion of this instrument is clearly shown in Figs. 
75, 76 and 77, and the method of adjustment is 
described on the following pages. 

Model D, Fig. 75—Adjusting low speeds:— 
Close needle valve by turning low speed screw 
to the left until arm U slightly leaves contact 
with the cam. Then turn to the right one and 
one-half turns, open throttle one-quarter, prime 
carburetor and start motor. Close throttle until 
motor runs slowly without stopping. Turn low 
speed screw to the left one notch at a time until 
motor idles smoothly. If motor does not throttle 
low enough turn screw in stop arm to the left 
with a screw driver. Carburetor is now adjusted 
for low speed. 

Adjusting high speed:—Now open the throt¬ 
tle slowly until wide open. Should motor back¬ 
fire turn high speed adjusting screw to the right, 
a half turn at a time, until motor runs without 
a miss. Should motor not backfire turn high 
speed adjusting screw to the left until it does, 
then to the right until motor runs smoothly and 
powerfully. 


180 


The Automobile Handbook 


Do not use low speed adjustment to get a cor¬ 
rect mixture at high or intermediate speeds. 

Should motor backfire or mixture be too light 
at intermediate speeds (throttle about % open) 



Fig. 75 

Rayfield Carburetor, Model “D”. A, Float Cham¬ 
ber. B, Mixing Chamber. C, Flange. D, Throt¬ 
tle Lever. E, Gasoline Intake. H, Gas Arm. J, 
Dash Adjustment. K, Air Valve. L, Needle 
Valve. M, Regulating Cam. P, Air Adjustment. 
R, Air Lock. S, Drain Plug. T, Priming Cap. 
U, Needle Arm. F, Water Connection. G, 
Priming Lever. N, Low Speed Adjustment. O, 
High Speed Adjustment. V, Primary Air In¬ 
take. W, Cam Shaft. 

turn air valve adjustment P to the right a turn 
or two, thus increasing the spring tension and 
decreasing quantity of air slightly. 

Remember that it is best to use all the air that 
the motor will handle without being sluggish. 

Do not change the float level. It is correctly 
set at the factory. Always prime carburetor 





















The Automobile Handbook 181 

well before starting motor. Pull steadily ou 
primer string. Don’t jerk. 

Do not cut down the air supply, unless the 
gasoline adjustments fail to give you a powerful 
and fast mixture. 

If motor does not get the correct mixture at 
intermediate speed or high speed, do not try to 
remedy it through a low speed adjustment. Re¬ 
member, the low speed adjustment is to be ad¬ 
justed only when the motor is running idle. 

In starting motor, do not open throttle more 
than one-quarter. The motor will start more 
readily with the throttle slightly opened and it is 
harmful as well as useless to race the motor in 
starting. 

Before cranking motor pull dash button up. 
After motor has “warmed up” push dash button 
down to Running Position. 

In stopping motor pull up dash button, open 
throttle about ^4 inch, and switch off ignition, 
thus leaving a sufficient volume of rich mixture 
in the cylinders, which assures easy starting 
when the motor is again used. 

Models G and L, Figs. 76 and 77, have no air 
valve adjustment and only two gasoline adjust¬ 
ments. 

Always adjust carburetor with dash control 
down. Low speed adjustment must be completed 
before adjusting “high.” 

Adjusting low speed:—With throttle closed, 
and dash control down, close nozzle needle by 
turning Low Speed adjustment to the left until 


182 


The Automobile Handbook 



Fig. 76 

Rayfield Carburetor, Model “G”. D, Throttle Arm. 
G, Priming Lever. H, Gasoline Arm. M, Regu¬ 
lating Cam. S, Drain Cock. U, Needle Valve 
Arm. X, Drain Cock. J, Gasoline Control Lock. 



Fig. 77—Rayfield Carburetor, Model “G”, Internal 
Construction 

























The Automobile Handbook 183 

Block U slightly leaves contact with the cam M. 
Then turn to the right about three complete 
turns. Open throttle not more than one-quarter. 
Prime carburetor by pulling steadily a few sec¬ 
onds on priming lever G. Start motor and allow 
it to run until warmed up. Then, with retarded 
spark, close throttle until motor runs slowly 
without stopping. Now, with motor thoroughly 
warm, make final low speed adjustment by turn¬ 
ing low speed screw to left until motor slows 
down, and then turn to the right a notch at a 
time until motor idles smoothly. 

If motor does not throttle low enough, turn 
stop arm screw A to the left until it runs at the 
lowest number of revolutions desired. 

Adjusting High Speed:—Advance spark 
about one-quarter. Open throttle rather quickly. 
Should motor backfire it indicates a lean mix¬ 
ture. Correct this by turning the high speed 
adjusting screw to the right about one notch at 
a time, until the throttle can be opened quickly 
without a backfiring. 

If “loading ’ 9 (choking) is experienced when 
running under heavy load with throttle wide 
open, it indicates too rich a mixture. This can 
be overcome by turning high speed adjustment 
to the left. 

Adjustment made for high speed will in no 
way affect low speed. Low speed adjustment 
must not be used to get a correct mixture at high 
speed. Both adjustments are positively locked. 

Starting:—Before starting motor when cold 


184 


The Automobile Handbook 


observe the following. Open throttle not more 
than one-qnarter. Enrich the mixture by pull¬ 
ing up dash control. Prime carburetor by pull¬ 
ing on priming lever G for a few seconds. 

When stopping motor, pull up dash control. 
Open throttle about one-quarter and switch off 
ignition. This leaves a rich mixture in the 
motor, which insures easy starting. 



Fig. 78 

Schebler Carburetor, Model “D”. A, Auxiliary Air 
Valve. C, Choke Valve. D, Drain Cock. F, 
Float. M, Spray Nozzle. G, Gasoline Inlet. N, 
Air Valve Adjustment. S, Air Valve Spring. T, 
Throttle Valve Lever. V, Gasoline Adjustment 
Valve. 

Raising dash control enriches the mixture by 
lifting the nozzle needle. Control button should 
be down for running, except when a richer mix¬ 
ture is required. 

Pull button up full distance for starting. 






The Automobile Handbook 


185 


Adjustment of carburetor should always be 
made with dash control down and motor warm. 

Schebler Carburetors. This make of instru¬ 
ment has been built in a number of different 
models, the first one of which to be used in large 
numbers was the Model D, Fig. 78. All of the 
important types of Schebler carburetors now in 
use are described and instructions given for their 
adjustments on the following pages. 



Valve. B, Gasoline Needle Valve. C, Priming 
Lever. D, Intermediate Speed Cam. E, High 
Speed Cam. 


The Model L carburetor, Fig. 79, is a type of 
lift needle carburetor and is so designed that the 
amount of fuel entering the motor is automatic¬ 
ally controlled by means of a raised needle work¬ 
ing automatically with the throttle. The adjust¬ 
ment or control of gasoline in this instrument 

























186 


The Automobile Handbook 


can be adjusted for low, intermediate or high 
speed, each adjustment being independent and 
not affecting either of the other adjustments. 

In adjusting the carburetor, first make adjust¬ 
ment on the auxiliary air valve A so that it seats 
firmly but lightly; then close the needle valve by 
turning the adjustment screw B to the right 
until it stops. Do not use any pressure on this 
adjustment screw after it meets with resistance. 
Then turn it to the left from four to five com¬ 
plete turns and prime or flush the carburetor by 
pulling up the priming lever C and holding it 
up for about five seconds. Next, open the throt¬ 
tle about one-third, and start the motor; then 
close the throttle slightly, retard the spark and 
adjust throttle lever screw F and needle valve 
adjusting screw B so that the motor runs at the 
desired speed and fires on all cylinders. 

After getting a good adjustment with the 
motor running idle, do not touch the needle valve 
adjustment again, but make all intermediate and 
high speed adjustments on the dials D and E. 
Adjust pointer on the first dial D from the 
number 1 towards 3, about half way between. 
Advance the spark and open throttle so that the 
roller on the track running below the dials is 
in line with the first dial. If the motor backfires 
with the throttle in this position, and the spark 
advanced, turn the indicator a little more toward 
number 3; or if the mixture is too rich turn the 
indicator back or toward number 1, until motor 
is running properly with the throttle in this posi- 


The Automobile Handbook 187 

tion, or at intermediate speed. Now, open the 
throttle wide and make adjustment on the dial 
E for high speed in the same manner as for in¬ 
termediate speed on dial D. 

In the majority of cases in adjusting this car¬ 
buretor the tendency is to give too rich a mix¬ 
ture. In adjusting the carburetor both at low, 
intermediate and high speeds, cut down the gaso¬ 
line until the motor begins to backfire, and then 
increase the supply of fuel, a little at a time, 
until the motor hits evenly on all the cylinders. 
Do not increase the supply of gasoline by turn¬ 
ing the needle valve adjusting screw more than 
a notch at a time in the low-speed adjustment, 
and do not turn it any after the motor hits regu¬ 
larly on all cylinders. In making the adjust¬ 
ments on the intermediate and high speed dials, 
do not turn the pointers more than one-half way 
at a time between the graduated divisions or 
marks shown on the dials. 

The Model R Schebler carburetor, Fig. 80, is 
a single jet raised needle type of carburetor, 
automatic in action. The air valve controls the 
lift of the needle and automatically proportions 
the amount of gasoline and air at all speeds. 

The Model R carburetor is designed with an 
adjustment for low speed; as the speed of the 
motor increases the air valve opens, raising the 
gasoline needle, thus automatically increasing the 
amount of fuel. The carburetor has but two ad¬ 
justments—the low speed needle adjustment, 
which is made by turning the air valve cap and 


188 


The Automobile Handbook 


an adjustment on the air valve spring for chang¬ 
ing its tension. 

This carburetor has an eccentric which acts on 
the needle valve, intended to be operated either 
from the steering column or from the dash, and 
insures easy starting, as by raising the needle 
from the seat an extremely rich mixture is fur¬ 
nished for starting, and for heating up the motor 
in cold weather. A choker in the air bend is also 
furnished. 



Fig. 80 

Schebler Carburetor, Model “R”. A, Low Speed 
Adjustment. B, Starting Cam Lever. C, Needle - 
Valve Connection. D, Starting Cam. E, Needle 
Valve. F, High Speed Adjustment. 

When carburetor is installed see that lever 
B is attached to steering column control or dash 
control, so that when boss D of lever B is against 
stop C the lever on steering column control or 
dash control will register “Lean” or “Air.” 
















The Automobile Handbook 189 

This is the proper running position for lever B. 

To adjust carburetor turn air valve cap A 
clockwise or to the right until it stops, then turn 
to the left or anti-clockwise one complete turn. 

To start engine open throttle about one-eighth 
or one-quarter way. When motor is started let 
it run till engine is warmed, then turn air valve 
cap A to left or anti-clockwise until engine hits 
perfectly. Advance spark three-quarters of the 
way on quadrant, if engine backfires on quick 
acceleration turn adjusting screw F up (which 
increases tension on air valve spring) until ac¬ 
celeration is satisfactory. 

Turning air valve cup A to right or clockwise 
lifts needle E out of nozzle and enriches mix¬ 
ture ; turning to left or anti-clockwise lowers the 
needle into nozzle and makes mixture lean. 

When motor is cold or car has been standing, 
move steering column or dash control lever to¬ 
wards “Gas” or “Rich” which lifts needle E 
out of gasoline nozzle and makes rich mixture 
for starting. As motor warms up, move control 
lever gradually back towards “Air” or “Lean” 
to obtain best running conditions until motor has 
reached normal temperature. When this tem¬ 
perature is reached control lever should be at 
“Air” or “Lean.” 

For best economy and power, the slow speed 
adjustment should be made as lean as possible. 

Stromberg Carburetors are made with a noz¬ 
zle, the opening in which is not adjustable. This 
nozzle is a separate part of the carburetor and 


190 


The Automobile Handbook 


is screwed into place from below. In order to 
adjust the gasoline flow it is necessary to remove 
one nozzle and replace it with one having a larg¬ 
er or smaller opening. The nozzles are marked 
according to drill gauge sizes and the opening 
becomes larger as the number becomes lower, that 
is to say, a number 59 is larger than a number 
60 and a number 58 is larger than a number 59. 

If, after making low speed adjustment it is 
found that the air valve remains off its seat or 
that indications of a rich mixture are still pres¬ 
ent, the nozzle is too large. If the high speed 
adjustment has to be screwed very tight it indi¬ 
cates that the nozzle is too small. In changing 
nozzles do so one size at a time, that is, do not 
drop from number 60 to a number 58, but use 
a 59 first. 

The several types of Stromberg carburetors 
that have been fitted up to the present time are 
described and adjustment instructions given in 
the following pages. 

Instructions for type A. Type A, Fig. 81, is 
a water jacketed carburetor. It has its spray 
nozzle PN mounted in the center of the carbure¬ 
tor with its point 3-16 of an inch above the 
normal gasoline level and surrounded by a 
modified venturi tube. This nozzle is propor¬ 
tionate in size to the carburetor and never needs 
attention or adjustment. 

After the carburetor is installed and the gaso¬ 
line turned on, note the level of the gasoline in 
the float chamber. It should be about one inch 


The Automobile Handbook 


191 


from the lower edge of the glass. This level is 
adjusted at the factory and should be right. In 
case it is obviously wrong, remove the dust cap 
D and turn the adjusting screw S until the 
proper level is obtained. If the gasoline is too 
high, screw the nut down. If gasoline is too 
low, screw the nut up. Don’t change unless 
absolutely necessary. 



To start the motor close the valve S3 in the 
hot air horn H. The motor should then start 
on the second or third turn of the crank. If 
not, open the valve and it ought to start on 
the next turn. Great care should be taken to 
see that this valve is instantly opened as the 
motor starts, and is kept open. 

Season adjustments. Open and close shutter 
SA—open in summer and closed in winter. 

Low speed adjustment. Turn up the adjust- 









192 


The Automobile Handbook 


ing nut A until the spring SI, which is the low 
speed spring, seats the valve lightly. See that 
the high speed spring above B is free and does 
not come in contact with the nut on top of the 
auxiliary air valve stem. Start the motor and 
turn nut A up or down until motor idles prop¬ 
erly. This is the low speed adjustment. 

High speed adjustment. Advance the spark 
and open the throttle. If the motor backfires 
through the carburetor, turn high speed adjust¬ 
ing nut B up until backfiring ceases. If, with 
this adjustment and running at low speeds, 
motor gallops, or the carburetor loads up, the 
mixture is too rich. The nut B should then be 
turned down until galloping or loading ceases. 
This is the high speed adjustment. The spring 
above nut B should always have at least 1-32 
inch clearance between it and the nut at the top 
when the motor is at rest. 

Instructions for type B. Type B, Fig. 82, 
is a concentric type carburetor. It has its spray 
nozzle PN mounted in the center of the car¬ 
buretor, and in the center of the float chamber, 
with its point 3-16 of an inch above the normal 
gasoline level and surrounded by a modified 
venturi tube. 

The level of the gasoline in the float chamber 
should be about 15-16 of an inch from the lower 
edge of the glass marked X. This level is adjust¬ 
ed at the factory and should be right. In case 
it is wrong, remove the dust cap D and turn 
the adjusting screw S until the proper level is 


The Automobile Handbook 193 

obtained. If the gasoline is too high screw the 
nut down. If the gasoline is too low screw the 
nut up. Don’t change unless absolutely neces¬ 
sary. 


Fig. 82 

Stromberg Carburetor, Model “B” 

Low speed adjustment. Turn up the adjust¬ 
ing nut A until the spring SI, which is the low 
speed spring, seats the valve lightly. See that 
the high speed spring above B is free and does 
not come into contact with the nut on top of 
the auxiliary air valve stem. Start the motor 
and turn nut A up or down until motor idles 
properly. This is the low speed adjustment. 

High speed adjustment . Advance the spark 
and open the throttle. If motor backfires 
through the carburetor, turn high speed adjust¬ 
ing nut B up until backfiring ceases. If, with 
this adjustment and running at low speeds 
motor gallops, or the carburetor loads up, the 













194 The Automobile Handbook 

mixture is too rich. The nut B should then be 
turned down until galloping or loading up 
ceases. This is high speed adjustment. The 
spring above nut B should always have at least 
1-32 inch clearance between it and the nut at 
the top when the motor is at rest. 


L 



Stromberg Carburetor, Model “C” 


Instructions for type C. Type C, Fig. 83, 
is equipped with two separate gasoline spray 
nozzles. The first or primary nozzle PN is 
mounted in the venturi tube V; this nozzle 
supplying sufficient gasoline for all speeds up to 
twenty or twenty-five miles per hour. The sec¬ 
ond or auxiliary nozzle is mounted just beneath 
the secondary gasoline needle valve ANV in 
the auxiliary air passage AA, and is opened by 
the lever L operating over a fulcrum F by the 
opening of the auxiliary air valve AV. 






The Automobile Handbook 


195 


Turn up the lower adjusting nut N, located 
underneath the auxiliary air valve, so that the 
valve is brought up to seat, then give two full 
turns to the right as a starting adjustment. 
This valve should be seated on extreme idle. 
The spring SI is the low speed spring and does 
the work up to the opening of the auxiliary 
needle. 

Start the motor and turn low speed nut N up 
or down until the motor idles properly, then 
advance the spark, open the throttle, and if the 
motor backfires turn nut LN down until it 
ceases. If mixture is too rich, turn it up. Be 
sure that nut LN and lever L have some clear¬ 
ance on low speed. 

The proper gasoline level is about 1 inch 
from the lower edge of the glass. If more than 
% inch either way remove the dust cap and 
adjust by screws. 

High speed adjustment . The high speed is 
regulated by the lock nut LN on top of the 
auxiliary air valve. As it is raised or lowered 
it determines the point at which the auxiliary 
needle valve ANY will be brought into play. 
To lock nut LN should be about 3-32 of an inch 
above the lever L for normal adjustment, but 
this distance can be increased or decreased to 
suit the motor. 

To find primary nozzle size. If the mixture 
is too rich on low speed after adjustments are 
made according to instructions, take out the 
plug P and remove the nozzle PN with a screw- 


196 


The Automobile Handbook 


driver. Insert smaller nozzle (59 is smaller 
than 58). If the mixture is too lean on low 
speed a larger nozzle should be inserted. If 
the engine misses on low speed it may be caused 
by an air leak, and all the joints between the 
carburetor and the motor should be examined 
before a large nozzle is inserted. 



Stromberg Carburetor, Model “G” 


Instructions for type G. Type G, Fig. 84, 
is a non-water-jacketed model furnished in 
either single or double jet according to motor 
requirements. 

Air adjustments. There are only two adjust¬ 
ments that ever need attention, A, the low speed 
nut, and B, the high speed nut. 

With the motor at rest, set the high speed nut 
B so there is at least 1-16 of an inch clearance 
between the spring G and the nut X above it. 
This is imperative. 






The Automobile Handbook 197 

Set the low speed nut A so the air valve E is 
seated lightly. Do not adjust carburetor until 
motor is thoroughly warmed up. When motor 
is warm and with spark retarded adjust nut 
A up or down until motor runs smoothly at low 
speed. To determine proper adjustment open 
the air valve with finger by depressing X 
slightly. If, when so doing, motor speeds up 
noticeably it indicates too rich a mixture and 
A should he turned down notch by notch. If, 
on the other hand, motor dies suddenly when 
slightly opening the air valve it indicates too 
lean a mixture and A should be turned up until 
this is overcome. 

Once properly set for idling do not change 
this adjustment when making the high speed 
adjustment. 

Advance the spark at the normal position and 
open the throttle gradually. If motor back¬ 
fires through the carburetor it is positive in¬ 
dication of too lean a mixture and nut B should 
be turned up notch by notch until this is over¬ 
come. 

If mixture is too rich, as indicated by loading 
of the motor and heavy black smoke from the 
exhaust, turn B down until motor operates 
properly. A further test for the correct mix¬ 
ture at high speed can be made by depressing 
the air valve when the motor is running at this 
speed. If when so doing motor speeds up it 
indicates too rich a mixture. 

Turning either adjusting nut up means a 


198 


The Automobile Handbook 


richer mixture or more gas. Down means a 
leaner mixture or more air. To get highest effi¬ 
ciency from this carburetor, hot air equipment 
should be used. 

Double jet type. If, after following the in¬ 
structions given below, and with the motor run¬ 
ning idle at low speed, the air valve E remains 
tightly seated, it indicates too small a primary 
nozzle C, and a larger one should be substi¬ 
tuted. If with the proper adjustment, and after 
stopping the engine, the air valve hangs off its 
seat the primary nozzle is too large and a 
smaller one should be used. To change the pri¬ 
mary nozzle remove the petcock, insert a narrow 
screwdriver and unscrew the nozzle. 

If the mixture at low speed is correct, but in 
order to get the proper high speed adjustment 
it is necessary to turn the nut B up so far that 
the spring G is in contact with X above it, after 
the engine has been stopped, it indicates that 
the auxiliary nozzle J is too small and a larger 
one should be used. If it is necessary, in order 
to get the proper high speed adjustment, to turn 
the nut B down so that there is more than % 
inch clearance between G and X when the en¬ 
gine is idle, it indicates too large an auxiliary 
nozzle and a smaller one should be used. 

Instructions for types H and HA. There are 
only two adjustments on this carburetor, Fig. 
85. A, the low speed, and B for high speed. 
A is a needle valve, seating in an open nozzle, 
the opening of which is usually two sizes larger 


The Automobile Handbook 399 

than is ordinarily necessary, and which per¬ 
mits an increase in gasoline flow to that extent 
or allows a complete closing. The high speed 
adjustment controls the flow of gasoline for 
high speeds by regulating the time at which the 
secondary needle valve begins to open. 



Fig. 85 

Stromberg Carburetor, Models “H” and “HA” 
To adjust, set the high speed nut B so that 
there is at least 1-32 of an inch clearance be¬ 
tween it and the needle valve cap above it at 
X when the air valve E is on its seat. The 
needle valve does not begin to open until B 
comes into contact with X. Before starting the 
engine be sure that the rocker arm of the dash 
adjustment on the carburetor is not in contact 
with the collar above it at Z when the steering 
post button is all the way down. 

To start the engine, pull the steering post 
control to its highest position, thus producing a 








200 


The Automobile Handbook 


rich mixture. In cold weather it may also he 
necessary to close the air supply in the hot air 
horn by means of a rod connected to B. This 
should be again opened as soon as the engine 
starts. As the engine warms up, gradually 
lower the steering post control and make sure 
that it is at its lowest position before commenc¬ 
ing to adjust the carburetor. 



Fig. 86 

Stromberg Carburetor, Model “K” 


The mixture at low speed is controlled by the 
needle valve A. If too rich is indicated, by the 
engine “rolling” or “loading,’’ turn A up or 
anti-clockwise. If the mixture is not rich 
enough, turn A down or clockwise. To adjust 
high speed, advance the spark and open the 
throttle. If the mixture is not rich enough 
at high speeds, turn B up or anti-clockwise, 
and if the mixture is too rich turn B down or 
clockwise. 

Instructions for types K and KO. The nut 





The Automobile Handbook 201 

A is the only adjustment on this carburetor, 
Fig. 86. The stem of this nut supports the 
lower end of a spring that controls the air 
valve. This air valve opens downward into the 
air chamber. Turning the nut A clockwise or 
down tightens this spring, admitting less air 
and producing a richer mixture. Turning A 
in the opposite direction or anti-clockwise pro¬ 
duces a leaner mixture. 

Before starting the engine turn A anti-clock¬ 
wise until a point is reached where, when lift¬ 
ing or pulling up on A, a decided click is 
heard. This is the air valve coming in contact 
with its seat. Then turn A clockwise or down 
until the click is no longer obtained. This turn¬ 
ing should be a notch at a time, and when the 
click can not be heard, turn two more notches 
in the same direction. To start the engine, 
raise the steering post control to its highest 
position. Gradually lower the control as the 
engine warms up, and make sure that this con¬ 
trol is at its lowest position before starting to 
adjust the carburetor. With the engine warm, 
turn A up or down, notch by notch, until the 
engine idles properly. It should not be neces¬ 
sary to change the initial setting more than a 
few notches. 

The high speed mixture can only be affected 
by changing the nozzle. If the high speed 
mixture is too thin, so that slightly closing the 
dash throttle valve R causes an increase of en¬ 
gine speed, a larger nozzle should be used. If 


202 


The Automobile Handbook 


the high speed mixture is too rich use a smaller 
nozzle. The nozzle size furnished is based on 
18 inches of hot air tubing. If this tubing is 



Zenith Carburetor, Model “0”. B, Float Control 
Lever. Cl, Dust Cap. D, Strainer Body. Dl, 
Wire Gauze. E, Gasoline Channel. F, Float. 
G, Main Jet. Gl, Needle Valve. G2, Float 
Control Collar. I, Gas Well Opening. H, Sec¬ 
ondary Nozzle. J, Gasoline Well. K, Gasoline 
Passage. L, Drain Plug. N, Idling Adjust¬ 
ment. S, Float Valve Opening. T, Throttle. 
X, Choke Tube. 











































The Automobile Handbook 203 

more than 24 inches long, one size smaller noz¬ 
zle can probably be used, while if the tubing 
is less than 10 inches long one size larger may 
be required. 

Zenith Carburetor, Model 0. This carbure¬ 
tor, a cross-section of which is shown in Fig. 
87, consists of a float chamber, a carbureting 
chamber, a system of nozzle and air passages 
and a hot air sleeve. 

Gasoline from the tank enters the strainer 
body D, passes through the wire gauge Dl, and 
enters the float chamber through the valve seat 
S. As soon as the gasoline reaches a predeter¬ 
mined height in the float chamber the metal 
float F, acting through the levers B and collar 
G2, closes the needle valve G1 on its seat. To 
see if there is any gasoline in the carburetor 
remove dust cap Cl. If the needle valve can be 
depressed with the finger there is no gasoline in 
the carburetor. From the float chamber to the 
motor gasoline flows through three different 
channels in various quantities and proportions 
according to the speed of the motor and degree 
(if throttle opening. With the throttle fully 
open, most of the gasoline flows through the 
channel E and main jet G. Some flows through 
compensator I, then through K to the cap jet 
H, which surrounds the main jet. The main 
jet and cap jet work together and their com¬ 
bination furnishes the mixture required for 
various engine speeds. At slow speed when the 
throttle T is nearly closed they give but little 


204 The Automobile Handbook 

or no gasoline, but, as there is considerable suc¬ 
tion on the edge of the butterfly the tube J, 
terminating in a hole near the edge of the but¬ 
terfly, picks up gasoline, which is measured out 
by a small hole at the top of the priming plug. 
The well over compensator I is open to the air 
through two holes, one of which is indicated be¬ 
low the priming plug in the illustration. These 
air openings are important. 

The hot air sleeve is provided with an air 
strangler actuated by a lever and having 
a coiled spring to bring it back to the open posi¬ 
tion. The flexible hot air tubing is attached to 
this sleeve and feeds the carburetor with air 
that has been heated by contact with the ex¬ 
haust pipe. 

To start the engine open the throttle a little 
way. There will be a strong suction on the tube 
J which will raise the gasoline and thus prime 
the motor. The only adjustment that may be 
useful is the slow speed adjustment, which is 
obtained by the screw 0. Tightening this screw 
restricts the air entrance to the slow speed noz¬ 
zle, giving a richer mixture. 

It is essential that none of the parts shall be 
tampered with, or the size of the jets altered by 
reaming or hammering. These jets are tested 
for actual flow of gasoline and brought to a 
standard. The nominal size of the hole in hun¬ 
dredths of a millimeter is stamped on the jet: 
the higher the number, the larger hole. 

Variables that can be modified for the initial 


The Automobile Handbook 205 

setting of the carburetor: First, the choke tube 
X. This choke tube is held in place by set 
screws and can be removed after taking apart 
the throttle. 

It is really an air nozzle, of such a stream 
line shape that there will be no eddies in the 
air drawn through it. 

For a 4 cylinder engine whose maximum speed 
is 1,500 R. P. M., to obtain the choke number, 
multiply the bore in inches by five and add one 
to the result. 

For 6 cylinder, take a choke one size larger 
up to 4%" bore and two sizes larger above 4%" 
bore. 

If the engine is so built that it can turn up 
to 1,800 R. P. M., increase these results 8%; up 
to 2,000 R. P. M., increase 16%; up to 2,500 
R. P. M., increase 25%. 

A choke tube too small will cause a loss of 
charge at high speed, the car will not attain its 
proper speed. 

A choke tube too large will lead to irregulari¬ 
ties when slowing down and picking up. 

Second—Main Jet C. The effect of this jet 
is most marked at high speed, 1,400 R. P. M. 

Third—Compensating Jet I. This jet, which 
compounds with the main jet, exerts its maxi¬ 
mum influence at lower speeds, 600 R. P. M., 
and in picking up. 

Fourth—Secondary Well P. This regulates 
the amount of gasoline used when idling. 


206 The Automobile Handbook 

Change Speed Gearing. 

The means provided for securing different 
ratios of speed between the engine and road 
wheels of the car is oftentimes called the 
transmission. Strictly speaking, the transmis¬ 
sion system includes all the parts between en¬ 
gine and wheels; the clutch, universals and 
rear axle parts, as well as the mechanism that 
allows various forward speeds and the reverse. 
The Change Speed Gear takes various forms; 
planetary, friction, sliding gear and magnetic, 
each being described. 

Change Speed Gears. When a gasoline en¬ 
gine is loaded above a certain limit it slows 
down, and the intervals of time between ex¬ 
plosions in each cylinder become so far apart 
that the engine begins to labor, and will finally 
stop altogether, unless some means is provided 
whereby the revolutions of the engine may be 
increased without^ increasing the number of 
revolutions of the driven shaft, or car axle. 
This is accomplished by means of the change 
speed gear, of which there are two classes, viz., 
those in which an infinite series of variations 
in speed ratio is possible, and those in which 
only a comparatively small number of step-by- 
step ratios can be utilized. In the first class 
are several styles of belt and friction disc 
drives, while in the second class are the change 
speed gears proper, namely, sliding gears, indi¬ 
vidual clutch gears, and planetary gears. 

Belt and friction drives constitute the only 


The Automobile Handbook 20? 

practical forms of change speed devices in 
which variation from the highest to the lowest 
speed may be possible. In other change speed 
gears the ratio is changed by passing from one 
to another in a series of definite steps. 



Friction Drive. One/ of the most simple 
methods of changing the speed ratio between 
the motor and the driven shaft is the friction 
drive, which in its simplest form consists of 
two discs at right angles to each other, see Fig. 






































208 


The Automobile Handbook 


88, in which b is the fly wheel, the exterior sur¬ 
face of which is made a true plane, and usually 
covered with a special friction metal. A hori¬ 
zontal shaft located crosswise of the car body 
carries a friction pulley c, in close proximity to 
the surface of the fly wheel b. 

Friction pulley c while secured from turning 
on shaft, may at the same time be shifted along 
at the will of the operator, and thus be 
brought in contact with any portion of the sur¬ 
face of the flywheel, from its center to its outer 
edge. The shaft also carries on its outer ends, 
the sprocket wheels which drive chains e and 
f, by means of which the power is transmitted 
to the drivers. In this device if the friction pul¬ 
ley c be brought in contact with the exact cen¬ 
ter of fly wheel b, no motion will be imparted 
to c, but if it be moved outward from the 
center of the flywheel it will revolve, the num¬ 
ber of revolutions it makes being governed by 
its distance from the center. The maximum 
speed is attained by friction pulley c when it is 
brought into contact with the surface of the fly 
wheel near the periphery of the latter. All po¬ 
sitions of friction pulley c upon one side of the 
center of fly wheel b impart a forward motion 
to the car, and all those on the other side of the 
center impart a reverse, or backing motion. The 
traversing movement of pulley c along its shaft 
is usually produced by a hand lever provided 
with a notched quadrant, whereby the pulley is 
held at all times in some one of the many posi- 


The Automobile Handbook 


209 


tions giving graduations of speed. The method 
usually employed for making and breaking con¬ 
tact between the friction pulley, and flywheel 
face, consists in mounting the bearings of the 
cross, or countershaft in swinging brackets. An¬ 
other method is to mount these bearings in ec¬ 
centric housings, a slight rotation of which in 
the bearing brackets will cause the shaft and 
with it the pulley to approach, or recede from 
the face of flywheel b. The movement of the 
shaft toward, or away from the flywheel is pro¬ 
duced by a ratchet retained pedal through a 
reducing linkage, which multiplies the foot 
pressure. 

Double Disk Friction Drive. The limitation 
of the single disc and wheel to small power, and 
light loads, has led to the development of the 
double disc, double wheel type of friction geai 
illustrated in Fig. 89. 

The engine shaft is extended, and carries two 
disc fly wheels A and B, while friction pulleys 
C and D are each carried upon one half of 
the cross shaft which is divided at its center. 
Friction pulleys C and D are made to slide 
along the shafts H and F, and are controlled 
by a common sliding mechanism, so that they 
always bear upon points of discs A and B, hav¬ 
ing the same velocities. Driving contact is ef¬ 
fected by swinging shafts H and F in a hori¬ 
zontal plane, and it is obvious that if one of the 
pulleys, D for instance, is pressed against the 
face of A, it will revolve in one direction, while 


210 


The Automobile Handbook 


if brought to bear on B it will revolve in the 
opposite direction, thus providing for a go- 
ahead, or a back-up motion being imparted to 
either friction wheel at will, dependent upon 
whether it is in contact with the forward, or the 




rearward disc. It is also evident that if one 
of the wheels, say D, is pressed against A, and 
the other wheel C is also pressed against B, 
their shafts will rotate in opposite directions. 
The ratio of the common angular velocity of the 





































The Automobile Handbook 


211 


wheels and their shafts to that of the discs is 
in proportion to their distance from the center 
of the discs. Sprockets upon the extremities of 
shaft H and F drive the road wheels by chains, 
and sometimes no differential is employed, 
power being shut off when turning comers, or, 
if not, the inevitable slip is divided between the 
frictional contacts, and the contacts of the tires 
with the road. A differential may be mounted 
in either shaft H or F at will. 

Instead of the two shafts H and F being sep¬ 
arate, they may be joined to form a continuous 
shaft and pivoted in the center. The shaft as 
a whole is capable of being slightly swung in a 
horizontal plane about its center, so as to bring 
friction wheel D in contact with one disc, and 
friction wheel C in contact with the other, thus 
producing either the forward or reverse drive. 
In this case a single sprocket is carried by the 
shaft and drives a live rear axle. 

Friction Drives—Materials For. In fric¬ 
tion drives, one of the surfaces in contact is 
generally a metal, while the other surface is 
composed of some kind of organic material, of 
a slightly yielding or conforming nature. Cast 
iron with cork inserts may be used for the me¬ 
tallic surface, the cork inserts serving to in¬ 
crease the co-efficient of friction, besides absorb¬ 
ing any oil that may accidently reach the sur¬ 
faces. Aluminum is no doubt the best material 
for the metallic surface, on account of its plastic 
nature. Copper also possesses similar proper¬ 
ties. For the non-metallic surface, leather is 
good so long as oil is kept from accumulating 


212 The Automobile Handbook 

on it, but its co-efficient drops rapidly as soon 
as oil gets between the contact surfaces. 

Some kind of vegetable fibre, made into a 
paper or mill board, seems to be the preferred 
material, and it is comomn to treat such paper 
with a tarry composition, which tends to raise 
the co-efficient of friction, as well as to render 
its value more nearly constant under the influ¬ 
ence of water and oil. 

The non-metallic friction face is the one worn 
out in service, or at least it wears the more rap¬ 
idly. This part of the combination, though of 
limited life, can be renewed at a comparatively 
small expense, and it fails only after giving due 
notice. It is the practice to make the disc face 
metallic, and the friction wheel rim non-metal¬ 
lic. Great care should be exercised in starting 
the car, as at such times the disc is liable to 
slip at speed upon the rim of the friction wheel 
which is then either stationary or revolving 
• very slowly, and flat spots may very easily be 
worn upon its surface. 

The Planetary Change Speed Gear. This 
system of transmitting the power at various 
speeds comprises a high-speed connection for 
the direct drive, and an arrangement of gears 
that reduces or reverses the motion when one 
or another drum on which these gears or pin¬ 
ions are mounted is held stationary. Most 
planetary systems give only two forward speeds 
and the reverse, but in some instances they are 
made to give three forward speeds. They are 


The Automobile Handbook 


213 


used chiefly on small automobiles, or runabouts; 
but when cheapness of construction is an object 
they are sometimes employed on touring cars. 

In Fig. 90 is shown one form of planetary 
system. The gear a is the only one keyed to 



the engine shaft b. The gears c, d and e all 
mesh with the gear a, and are made long enough 
to extend beyond a and mesh with the gears 
f, g and h in pairs. The last three gears in 
turn extend beyond the gears c, d and e, and 






214 The Automobile Handbook 

mesh with the gear i, which is keyed to a sleeve 
connected to the drum j. The gears c, d, e, f, 
g and h turn on pins fastened to the drum k, 
but only the gears c, d and e mesh with a, and 
only f, g and h mesh with the gear i which 
turns loosely on the shaft b. The internal gear 
1 meshes only with the gears c, d and e, and 
is rigidly connected to the sprocket m that 
drives the automobile. The cover n is attached 
to the face of the drum k by means of screws, 
thus forming an oil reservoir that keeps the 
gears well lubricated when the automobile is 
running. There are separate brake bands 
around the drums j and k, and a friction disc 
keyed to the shaft just outside of the drum j. 

When the friction disc is pressed against the 
drum j, the gear is held so that it must turn 
with the shaft; consequently, the entire me¬ 
chanism is locked together and the sprocket m 
turns at its highest forward speed. It now the 
friction disc is released and the brake band 
around the drum j is applied so as to hold it 
from turning, then the gear a turns the gears 
c, d and e, causing them to turn the gears f, 
g and h; but, as the gear i is held stationary 
with the drum j, the gears f, g and h, and also 
the drum k, to which they are attached, must 
revolve around the gear i in the same direction 
as the shaft turns, but more slowly. The gears 
c, d and e turn on pins that are fastened to the 
drum k; consequently, they revolve with it as 
they turn on their axes and thus cause the in- 


The Automobile Handbook 


215 



ternal gear 1 and the sprocket m to turn in the 
same direction as the shaft. This gives the slow 
forward speed. 


When the drum j is released, and the drum k 
is held by a brake band, the gears c, d and e 
are caused to turn on their pins, and conse¬ 
quently drive the internal gear 1 in a direction 


216 


The Automobile Handbook 



Fig. 92 

Combination Transmission and Differential Gear 


opposite to that of the engine shaft, driving the 
automobile backwards. When the brake bands 
and friction disc are all free from the drums, 
the gears turn idly, and if the engine is running, 
no motion is transmitted to the sprocket and 
the automobile stands still. 

A form of change speed gearing that is in 
use on a large majority of cars is that known 
as the sliding gear. All sliding gear trans- 





The Automobile Handbook 217 

missions consist of two principal shafts lying 
parallel to each other and placed one above the 
other or side by side. Each shaft carries a 
series of gears, those on one shaft being per¬ 
manently fastened against lengthwise move¬ 
ment, while those on the other shaft are capable 
of being moved along the shaft while turning 
with it. This latter set of gears is built.with 
either a square or key-waved hub and the shaft 
on which the set slides is made square or with 
spline keys to correspond. The gears on the 
other shaft are made of such sizes that when 
the sliding members are moved they come into 
mesh with the gears on the other shaft so that 
when together they form pairs, that is to say, 
when a gear on one shaft is in mesh with one 
on the other shaft it is impossible to cause 
any other gears to mesh at the same time. 

The gears are graduated in size so that the 
several pairs or combinations that may be 
formed vary in ratio, and in this way it is pos¬ 
sible to obtain different degrees of speed reduc¬ 
tions between the two shafts and therefore 
between the engine and road wheels. 

In forms of construction that use the two 
shafts exactly as described in the previous para¬ 
graphs, and in which one shaft is connected 
through the clutch to the engine and the other 
one through the drive parts to the rear wheels, 
the series of sliding gears is made with all of 
the gears fastened together so that there can be 
no relative motion between them, and in this 


218 


The Automobile Handbook 



Fig. 93 

Selective Sliding Change Speed Gears 













The Automobile Handbook 


219 


ease the entire sliding member is moved bodily 
along the shaft. This particular form is known 
as a progressive sliding gear. It is necessary, 
with this type of construction, to pass from one 
ratio to another in the same order for each 


operation, and if it is desired to pass from the 
extreme low ratio to the highest ratio, it is nec- 



Fig. 94 

Selective Sliding Gear With Disc Clutch in a 
Unit Power Plant. A, Clutch Shaft. B, Clutch 
Shaft Gear. C, Countershaft Gear. D, Second 
Speed Gear. E, Low Speed Countershaft Gear. 
F, Second Speed Sliding Gear. G, Low and Re¬ 
verse Sliding Gear. H, Sliding Gear Shaft.. 
essary to pass through all intermediate ratios. 
The progressive form of transmission is no 


longer fitted to cars and an extended descrip¬ 


tion is not considered necessary 


















































220 


The Automobile Handbook 


The type of sliding gear transmission that 
is most popular is called the selective sliding 
gear and with the exception of some important 
modifications is similar in operation and con¬ 
struction to the progressive type already de¬ 
scribed. Selective sliding gears are shown in 
Figs. 92 to 97 and the following description 
will apply more or less to all of them although 
the form shown in Fig. 94 is specifically cov¬ 
ered. It will be noted that the clutch is at the 
left hand end of the illustration, and through 
this clutch the power of the engine is trans¬ 
mitted to the shaft marked A. At the right 
hand end of the shaft A is carried a gear B, 
and this gear is in mesh with the gear C on 
the lower shaft of the transmission, it will there¬ 
fore be seen that whenever the clutch causes 
shaft A to revolve, gears B and C will also turn, 
and inasmuch as C is fastened solidly to the 
lower shaft of the transmission, this lower shaft 
will turn whenever the engine is running and 
the clutch engaged. The upper shaft in the 
transmission marked H is not made in one piece 
with shaft A, but its left hand end is made of 
a diameter sufficiently small to fit into a recess 
in the shaft A and in the hub of the gear B. 
This construction simply provides a bearing for 
one end of the shaft H so that it may revolve 
independently of shaft A. Shaft H is formed 
with four longitudinal keys integral, and on 
this shaft are mounted the gears F and G with 
their hubs formed with keyways to engage 


The Automobile Handbook 221 

the keys on shaft H. This construction allows 
the gears F and G to be moved lengthwise while 
turning with the shaft. Gears D and F are 
made of such diameter that when F is moved 
to the right it meshes with D and gears E and 
G will mesh when G is moved to the left. The 
right hand end of shaft H is fastened to the 
universal joint that leads to the rear axle. 



Sliding Gear Set for Separate Mounting 
The operation is as follows: With the en¬ 
gine running and the clutch engaged, power 
is transmitted through gears B and C to the 
lower shaft of the transmission, and inasmuch 
as gear C is larger than B, the lower shaft 
will run at a lower rate of speed than the clutch 
shaft. If now the gear G be caused to mesh 
with E, the shaft H will be revolved but at a 
still lower rate of speed than the bottom shaft. 






























222 The Automobile Handbook 

and inasmuch as H drives the rear axle it will 
be seen that the mechanism has given a positive 
drive at a speed much below that of the engine. 



Pig. 96 

Heavy Duty Selective Sliding Gear for Rear Axle 
Mounting 

When it is desired to secure a higher speed 
of the car relative to that of the engine, gears 

































































The Automobile Handbook 223 

G and E are withdrawn from each other and 
gear F is moved into engagement with D. It 
will be noted that gears D and F are approxi¬ 
mately the same size, and the upper shaft will 
then turn at a speed very nearly the same as 
that of the bottom shaft, but still less than 
the speed of the engine. This position is known 
as second speed or intermediate speed. 

When it is desired to secure a still higher 
ration of speed it is done by moving gears D and 
F out of engagement and then moving F to 
the left. Gear F carries one-half of a jaw, or 
toothed clutch, and gear B carries the other 
half of this same clutch. It will thus be seen 
that when F and B are together the clutch will 
be engaged and shaft A will drive shaft H at 
the same speed at which A is revolving. This 
provides high speed or direct drive. 

When it is desired to reverse the direction of 
motion of the car, gear G is moved into engage¬ 
ment with an idler gear that is not shown, and 
this idler gear is driven through another one 
on the bottom shaft of the transmission. The 
idler gear being interposed between the upper 
and lower transmission shaft gears causes the 
upper shaft to reverse its previous direction 
of motion. 

Certain variations of selective sliding gears 
are in use, one of which is shown in Fig. 
97. In this particular form the spur gears 
remain in mesh at all times, but neither set 
is keyed to its shaft. Between the gears are 


224 The Automobile Handbook 

mounted jaw clutches, and these clutches are 
keyed to the shaft. In place of moving thi 
gears into or out of engagement, the jaw 
clutches are moved, and depending on which 
clutch is moved and which way it is moved, 



Individual Jaw Clutch Sliding Gear Set 
the several sets of gears may be successively 
used, providing speed ratios similar to those 
in other forms of selective sliding gears. 

Magnetic Transmission. 

The difference between a car with magnetic 
transmission and other gasoline cars lies only 
in this transmission. There is no change in the 
engine or its operation. There is no change 
in the driving parts, save as regards their con¬ 
nection with the power. The parts omitted 
are the clutch and the clutch pedal, gears and 
shifting lever, flywheel, starter and lighting sys¬ 
tem, this one transmission unit taking the place 
of all. There is no mechanical connection be¬ 
tween the engine and the driving shaft. This 



























The Automobile Handbook 


225 


b 



Pig. 98 

The Owen Magnetic Transmission 

































































































































226 


The Automobile Handbook 


control also embodies an electric brake, and an 
automatic electric sprag, which absolutely pre¬ 
vents the car backing down hill, even though 
the motor is stalled. Should the engine be 
stalled on a hill, the car can be held without 
use of the brakes by simply moving this con¬ 
trol lever into high speed position. 

♦The power is never disconnected from the 
driving wheels of the car from the moment of 
starting up to the highest speed. 

The electrical apparatus consists of two units, 
Fig. 98, contained in a one-piece construc¬ 
tion : the one nearest to the engine has its mag¬ 
netic field pieces keyed to the engine crank¬ 
shaft and acts as a flywheel to the engine. Its 
armature is mounted on the propeller or drive 
shaft, hence it will be seen that both these parts 
can revolve. The second unit of the apparatus 
has stationary magnetic fields and its armature, 
as in the first case, is mounted on the propeller 
shaft. The first' unit becomes in turn a 
dynamo, magnetic clutch and a motor, the sec¬ 
ond unit, a motor and dynamo. 

A controller, with resistance coils internally 
contained, is bolted to the chassis frame for¬ 
ward of the dash, alongside of the engine, and 
is operated by a lever on the steering wheel 
through a small gearing at the bottom end of 
the steering column. 

By placing the control lever in the position 
‘ ‘ cranking, ’’ a battery is connected through 
the first unit, which in this instance becomes 


The Automobile Handbook 


227 


a motor, and once the engine is cranked, the 
lever can be placed in the “neutral’’ position 
until ready to start the car. 

On moving the control lever to the first po¬ 
sition, turning effort is produced by weak¬ 
ening, with a shunt resistance, the field of 
the first unit, which becomes a dynamo, and 



-Mid! \Wt Ml~ 1)1,« 


Fig. 99 

Principle of the Magnetic Transmission: A, En¬ 
gine Crankshaft. B, Revolving Field. C, Sta¬ 
tionary PMeld. D, Front Armature. E, Rear 
Armature. F, Propellor Shaft. 

the current generated, due to the electrical, 
slip between the magnetic fields and the arma¬ 
ture, is fed to the second unit, which, acting 
as a motor, produces a powerful starting torque. 
At the same time the pull of the magnetic fields 
of the first unit acts as a magnetic drag on its 
armature, and thus two forces assist in rotat¬ 
ing the propeller shaft, which, through the bevel 
drive, communicates power to the road wheels. 

The second position of the control lever cuts 
the resistance out of the first unit (dynamo) 
field and shunts through a high resistance some 
of the field current in the second unit (motor), 
thereby increasing the speed of the car. 























228 The Automobile Handbook 

In the third, fourth and fifth control lever 
positions, the second unit (motor) field is suc¬ 
cessively weakened until in the sixth control 
lever position, the field current is almost en¬ 
tirely shunted, so that previous to placing the 
control lever in the seventh (and last) position, 
the second unit is practically of itself not do¬ 
ing any work, apart from the fact that there 
is very little slippage between the first unit 
(dynamo) field and armature, resulting in gen¬ 
erating of but small current. In other words, 
the drive shaft is being carried around almost 
entirely by the magnetic drag of the first unit’s 
field on its armature. It will hence be seen that 
there is an electrical balance in effect through¬ 
out the entire sequence of operations. 

On placing the control lever in the seventh 
position, the first unit becomes what may be 
termed a ‘‘magnetic clutch,” the armature 
and field are closed-circuited, and an almost 
negligible slip only is required to generate suf¬ 
ficient current to enable the field to drag its 
armature around with it. 

The second unit with the control lever in 
high speed position becomes a generator, and 
when the car is running, charges the lighting 
and starting battery with a predetermined 
charge. 

From this point on the entire control is 
brought about by accelerating or decelerating 
the gas engine, the armature of the first unit 
follows its magnetic field promptly, generating 


The Automobile Handbook 229 

~f its own accord whenever necessary more cur¬ 
rent and hence getting more magnetic drag to 
bring it up to the same speed as the magnetic 
fields. Thus, so long as the control lever 
is in any position other than neutral on ac¬ 
celerating, an increase of speed is obtained, 
but on decelerating, the car coasts just like an 
ordinary car with the clutch released. This is 
brought about by the armature of the first unit 
traveling faster than the fields, and thus not 
generating any current until such a time as 
the car comes back to the speed, where the arm¬ 
ature of the first unit is traveling at the same 
or slightly lower speed than the field pieces 
or the engine, when again current is generated 
and the drive taken up as before. 

Should excessive grades be encountered where 
extra torque may be desired, the placing of the 
control lever in a lower position will give the 
desired result, and naturally by increasing the 
engine speed with the control lever in a lower 
position than high, more current will be gener¬ 
ated, due to the extra electrical slip, and thus 
give added torque. 

At neutral position the maximum electrical 
braking effect is obtained. Here the first unit is 
open-circuited and the second unit closed-cir- 
cuited and the magnetic braking reaction brakes 
the car to 10 miles per hour, below which speed 
the armature does not revolve within the motor 
field fast enough to create the braking effect, 
thus automatically holding the car on a grade at 
about the above speed. 


230 


The Automobile Handbook 


Chassis. The word chassis since its adoption 
into the English language, is taken to mean the 
frame, springs, wheels, transmission and in fact 
all mechanism except the automobile body. In 
its original French it does not mean all this, but 
is strictly restricted to mean the frame, or the 
frame and springs. 

Chauffeur. This term when literally trans¬ 
lated means the stoker or fireman of a boiler. 
The use of the word has been extended to the 
operator of a motor car, but does not usually re¬ 
fer to the paid driver, who is generally known 
as the mechanician or mechanic. 

Clutch. Clutches may be classified as fol¬ 
lows: a, cone; b, disc; c, band; cone clutches 
may, in turn, be subdivided as follows: a, metal 
to metal; b, leather faced; c, cork insert; while 
disc type may be classed as: a, leather faced; 
b, multiple disc; c, cork insert; and band 
clutches may be put down as of the a, constrict¬ 
ing, b, spiral, or c, expanding types. Clutches, 
of whatever type or class, have but one prime 
object, i.e., to enable the operator to start and 
stop the car without having to stop the motor. 
There is a secondary consideration, if we take 
into account the fact that it is convenient to be 
able to slip the clutch, on occasion. Some types 
lend themselves to this secondary purpose with 
greater facility than others, and it is also true 
that some clutches are most easy of application, 
all things considered. 

As clutches are at present designed, the ques¬ 
tion is, can slipping be tolerated? or, can 


The Automobile Handbook 


231 


clutches be slipped to control the speed of a 
car? It is believed not. The average clutch 
has very little of the character of the average 
braking system, and when it comes to brakes 
they do not last so long that it is desirable to 
wear them out sooner than they will naturally 
need replacement. In other words, it seems 
quite out of the question to consider the 
clutches of today as suitable for the double pur¬ 
pose of clutching and speed controlling, by way 
of slipping the clutch at will. It is not uncom¬ 
mon to hear autoists talking of the multiple 
disc clutch as one that undergoes little or no 
deterioration as a result of continuous slipping 
under variations of load. 

They seem to think that the large surface ex¬ 
posed, especially in view of the fact that the 
discs are submerged in oil, will prevent damage 
if the clutch is caused to slip. They forget that 
the discs are thin, and also that they are loose 
on the splines, keys, or feathers that prevent 
the discs from rotating. No member keyed onto 
a shaft will stand much abuse. This is espe¬ 
cially so, if the member has but little bearing 
surface on the key. Even a considerable num¬ 
ber of such members working in unison will 
fail to stand up under the work because the 
joint is not firm. Lost motion is bound to re¬ 
sult in more lost motion in a short while, and 
in a multiple disc clutch the discs soon fray out 
and interfere with each other, and with the 
clutching functions, within a space of time so 


232 


The Automobile Handbook 


short as to surprise even those most experi¬ 
enced in the use of this type. 

Band Clutch. A band, or friction ring, 
clutch, is shown in Fig. 100. The wheel which 
is connected to one of the shafts is shown at a, 
and the band, or ring which is connected to the 
other shaft and which is made in two parts, is 
shown at b and c. At d and e are curved arms 



Fig. 100 


pivoted at f and g. The links h and i connect 
these curved arms to the parts b and c of the 
band. By means of a fork, and tapered sleeve, 
not shown, the ends j and k of the arms are 
forced apart when the clutch is brought into 
use. This throws toward the shaft the ends 1 
and m of the levers d and e, and brings the two 
parts b and c of the clutch ring in contact with 





The Automobile Handbook 


m 

the friction or driving surface of the wheel a, 
which is thereby forced to turn with the driving 
shaft. The band clutch has had many expo¬ 
nents in the motor car art, but is open to cen¬ 
trifugal effects to such an extent that it re¬ 
quires considerable ingenuity to overcome trou¬ 
bles arising therefrom. At high engine speeds 
the operating levers have been so arranged as 
to lower tho normal expanding pressure. 



Fig. 101 


Cone Clutch. There are a number of modi¬ 
fications of this type of clutch, the general prin¬ 
ciples of which are illustrated in Fig. 101. The 
flywheel a is secured to the shaft b by means 
of bolts through the web of the wheel. At c is 
an expansion ring into which the friction cone 
d fits. The helical spring e holds the cone 
against the expansion ring with the required 






















234 


The Automobile Handbook 


amount of force. At f is a ball bearing that 
takes the end thrust when the cone is pulled 
away from the expansion ring. 

The arms g are coupled to the shaft that turns 
with the friction cone. Ordinarily the two parts 
of the clutch are held together by the pressure 
of the spring, and when it is desired to discon¬ 
nect the cone, a foot pedal is forced down so 
as to act on a fork and sleeve and pull the cone 



away from the expansion ring. When the pedal 
is released, spring e forces the clutch into action 
again. 

Fig. 102 is a sectional view of a form of 
leather faced cone clutch in which the male part 
of the cone moves axially toward the engine. 
Fig. 103 shows a clutch constructed on the 
same principle, but in place of having one 
strong actuating spring surrounding the axis, 
it has three weaker spiral springs near the pe« 














The Automobile Handbook 


235 


riphery of the male member. Fig. 104 is a verti¬ 
cal section of a clutch suitable for a 50 H. P. 
car. The cone angle is 13 degrees, and the di¬ 
ameter 16 inches, with a total frictional area of 
128 square inches, the axial pressure resulting 
from the spring being 375 lbs. A small spiral 
plunger spring A under the leather face B 
causes it to pick up the load more quietly and 
smoothly. Fig. 105 illustrates an early form 
of clutch intended for a car of about 20 H. P. 
One form of toggle joint is also shown at A. 



Fig. 103 


This clutch also has multi-springs for creating 
the proper frictional contact, and a peculiar 
form of spring application simple in the ex¬ 
treme. A multi-cone clutch is shown in section 
in Fig. 106. Its action is as follows: When the 
clutch engages, the smallest cone seizes first, 
commences to revolve and subjects the spiral 
springs between the next two clutches to tor¬ 
sional movement, which draws them together 
and brings the two outer cones into action; the 
idea being that the small clutch shall slip, tend 








236 


The Automobile Handbook 


to accelerate the car, that the medium clutch 
shall behave in a similar manner and that when 
the large clutch comes into play the three com¬ 
bined pick up the load and move the car. 

The so-called inverted cone is well illustrated 



in figure 107. The reversed cone is contained 
in an extension A, built onto the flywheel B. 
When the cone is disengaged it moves toward 
the engine, exactly reversing the action of the 
foregoing type. This clutch has its adherents, 






















































The Automobile Handbook 


237 


and it is a good one, differing very slightly, if 
properly assembled, in its efficiency from the 
direct-acting cone. It may be kept free from 
dirt and oil much more perfectly than in the 
other form. 

Disk Clutch. A clutch of the multiple-disc 
type is shown in Fig. 108. A two-arm spider 
a, keyed to the shaft b, serves to hold in place a 
number of metal discs c, between which are 
other metal plates d held on the sleeve e by 
means of a key f. The sleeve e is in turn keyed 



Fig. 105 Fig. 106 


to the shaft g, and to it is screwed a ring h 
having three pairs of lugs carrying three levers i, 
with rollers j at their outer ends, as shown. The 
other ends of the three levers press against the 
plate k when the clutch is engaged by an in¬ 
ward movement of the collar 1, plate k being 
free to move along the key f. Discs c are free 
to move longitudinally on the arms of the spi¬ 
der a, and also on sleeve e, around which they 
rotate when the clutch is out of engagement; 
but the arms of the spider, fitting into slots in 
the discs, cause them to rotate with the shaft b. 













238 


The Automobile Handbook 


The plates d are free to move longitudinally on 
the key f in the sleeve e; and since the sleeve is 
keyed to the shaft g, it is evident that, when 
in engagement with the discs c, the plates d 
must cause the shaft g to turn with the shaft b. 
The discs c and plates d run in an oil bath, 



obviating wear of the plates and discs. These 
are brought together forcibly by throwing the 
cone faced end of the collar 1 against the rollers 
j, thereby causing the ends of the three levers i 
to press the plates and discs together with suf¬ 
ficient force to cause the shafts b and g to rotate 
as one shaft. 
































The Automobile Handbook 239 

Five-plate Clutch. In the matter of the num¬ 
ber of plates in the disc clutch there is no agree¬ 
ment between designers. Some use a very large 
number of thin plates, as many as fifty or sixty, 
and others use a very small number, as few as 
six or eight; in fact, it may be said that the sin¬ 
gle disc clutch, which has only two frictional 



Fig. 108 

Five-Plate Clutch 

surfaces, is the lower limit. One arrangement 
which uses five plates is shown in Fig. 108. The 
diameter of the clutch is somewhat smaller 
than that of the single or three-plate types, but 
its diameter must be quite large in order to 
transmit considerable horse power. 

Clutches are made with various numbers of 
plates, from three to more than sixty, depending 
on the work required and the size and material 



























































240 The Automobile Handbook 

of which the plates are made. Plate materials 
include hardened steel for both members, steel 
and bronze, steel with cork inserts, and steel 
covered with some friction material similar to 
brake lining. 

Disc clutches using steel to steel are operated 
in a bath of oil. Those using bronze and steel 
may or may not operate in oil. As a general 
rule, clutches that are not enclosed are fitted 
with cork or an asbestos composition as the fric¬ 
tion material. However, either of the forms just 
mentioned operate satisfactorily in an oil bath, 
and it is, therefore, simply a question of choice 
with the designer. Unenclosed clutches are 
called “dry-plate clutches.” 

Clutch Troubles. One of the greatest 
sources of trouble for the novice lies in the 
clutch. This may be just right, it may be slip¬ 
ping, or it may be what is called fierce. The sec¬ 
ond manifests itself in such pleasant situations 
as climbing a hill when, with the engine run¬ 
ning at its highest speed and the proper gear 
engaged, the car starts to run backward instead 
of forward. Or on the level, with the engine 
racing and the high gear in, no speed results. 

The last condition shows itself in the sudden 
jumping forward of the car when the clutch 
has been let in, or it may even be so severe as 
to shear off the bevel driving gear when used 
with studded non-skid tires or any form that 
will not slip easily. 

To repair the first, look at the leather, if this 


The Automobile Handbook 


241 


is all in good shape with an apparently good 
surface, but has lubricating oil on it, wash the 
surface well with gasoline. It is not a bad idea 
to roughen the surface of the leather a little 
with a coarse file. 

The harsh or fierce clutch is remedied by the 
application of a proper oil for this purpose. 
Castor oil is universally used and a good way is 
to soak the complete clutch in it over night. 
This will cure a case of harsh leather, but it 
may be that the trouble is only a lack of adjust¬ 
ment of spring tension. Usually there is an ad¬ 
justing nut and a locking nut. Back off the 
latter and make an adjustment. Then tighten 
the lock nut to retain it. For the beginner, it 
is better to adjust a little at a time and make 
several successive jobs of it than to try to do 
it all at once. But always adjust it as soon as 
possible. 

The leather of the ordinary cone clutch by 
degrees acquires a sort of coarse surface glaze, 
which may or may not represent actual charr¬ 
ing of the leather, but is certainly due to the 
slipping it experiences. A leather with its sur¬ 
face so glazed has a very harsh action, since the 
surface is so hard that it grips all at once. The 
glazed surface will not absorb oil to any appre¬ 
ciable extent, a fact which is easily seen on at¬ 
tempting to dent the surface with a thumb nail 
after giving the oil time to soak in. In this con¬ 
dition the best thing to do is to put on a new 
leather. Unless the angle of the cone is too 


242 


The Automobile Handbook 


abrupt, a piece of ordinary belting will serve 
the purpose, provided it is of uniform thickness 
throughout. The belting may be soaked in 
neatsfoot oil over night before applying, and 
this will render it pliable enough to take the 
shape of the cone. If the old leather is retained 
in service it becomes almost essential to squirt 
a little oil on it every day or two, as otherwise 
it may take hold with such a jerk as to endan¬ 
ger the transmission shafts. If the cone re¬ 
leases by drawing backward, there are proba¬ 
bly openings in the web of the cone through 
which the spout of a squirt can may enter. Oil 
squirted into the flywheel interior will then 
quickly find its way to the clutch surface. 
Sooner or later, however, the leather will be¬ 
come glazed so smooth that it will not hold at 
all, and it is then liable to slip and burn up 
without warning. There are few things more 
exasperating than a clutch which cannot be 
made to hold properly, particularly when the 
car happens to be covering a bad stretch on 
which every available bit of power that can be 
transmitted to the rear wheels is necessary. The 
use of emergency remedies under such circum¬ 
stances most often leads to the necessity for 
clutch repairs, as road dirt and grit are not the 
best things possible for the leather facing, and 
frequently no other friction producing com¬ 
pound is to be had at the time. 

Renewal of Leather on Cone Clutch. Re¬ 
move the old leather by cutting off the rivets 


The Automobile Handbook 243 

on the underside, and driving the rivets through 
to the outside. Keep the old leather and use 
it as a pattern by which to cut the new piece. 
It will be much better, however, to purchase 
from the factory a new leather of the proper 
width and thickness. As a new leather will 
have considerable “give,” it must be stretched 
tightly over the cone. First cut one end of the 
leather square and fasten it to the cone with 
two rivets. The other end should not be cut at 
this stage of the work, but brought around to 
meet the fastened end, and, after tightly 
stretching it over the small end of the cone, 
fasten it with a single rivet. Then force the 
leather up onto the cone, drill out and counter¬ 
sink the holes and rivet up securely. The only 
knack in the operation is to keep the leather 
tight that it may be a snug fit on the cone. A 
loose leather will, naturally, be a dead failure. 
After the leather has been forced into its place 
the uncut end should be trimmed to make a 
good joint. Any unevenness may be trued up 
with a file. The new leather will readily ab¬ 
sorb several applications of castor oil before it 
becomes smooth and pliable. 

Care should be taken that the rivet heads are 
countersunk below the surface of the leather. 
In case they work flush, owing to the wearing 
down of the leather face, they should be riv¬ 
eted. The “biting” or jerky action of a cone 
clutch may often be traced to the rivets work¬ 
ing out, and this will frequently prevent the 


244 The Automobile Handbook 

clutch from being readily disengaged. Rerivet¬ 
ing will prove an effective remedy in this case, 
and considerable additional service may be had 
from the leather before it wears down to the 
rivet heads. 

Combustion Chamber. That part of an ex¬ 
plosive motor in which the gases are com¬ 
pressed, and then fired, usually by an electric 
spark, is known as the combustion chamber. 
The interior of the combustion chamber should 
be as smooth as possible and kept free from 
soot, or hard carbon deposits such as are in¬ 
duced by excessive lubrication, or the use of too 
rich an explosive mixture. 

It will be found to be no small task in design¬ 
ing an explosive motor with the usual form of 
valve construction and operation, to keep the 
combustion chamber down to the required di¬ 
mensions and at the same time have it free from 
bends or contracted passages between the com¬ 
bustion space and the valve chamber. 

Many attempts have been made to obviate 
this difficulty by making the combustion cham¬ 
ber simply a straight extension, or continuation 
of the cylinder. In this manner both the ad¬ 
mission and exhaust-valves can be placed in the 
cylinder itself and an ideal combustion space 
secured. This plan has, however, certain dis¬ 
advantages, from the fact that it not only 
lengthens the motor, but requires a more com¬ 
plicated form of valve operating mechanism 


The Automobile Handbook 245 

than if the valve chamber were at the side of 
the cylinder as is usual. 

Commutators, Ignition. The commutator of 
the ignition system of a multi-cylinder gaso¬ 
line motor has a three-fold use: To switch the 
battery current in and out of the electrical cir¬ 
cuit at the proper time—To transfer the bat¬ 
tery current successively from one coil to an¬ 
other—To vary the point or time of ignition 
of the explosive charge in the motor cylinder. 



The commutator shown in Figure 109 is for 
a four-cylinder motor and is designed for use 
with induction coils without vibrators, which 
are known as single-jump spark coils. The 
studs of the screws A and springs B are car¬ 
ried by insulated bushings located in the back 
of the commutator case. The nose of the cam 
C successively engages with the springs, caus¬ 
ing them in turn to make contact with their 
respective screws. The battery and coil circuit 
is completed through the screws A, and a 







246 


:The Automobile Handbook 


ground to the cam C, by means of the springs 
B, when in contact with their respective screws 
and the cam. 

This device is said to cause a good spark at 
the plug on account of the quick break between 
the spring and the screw, the electrical circuit 
being broken the instant the spring leaves the 
screw and before the cam has allowed the 
spring to resume its normal position. This form 
of commutator cannot be short-circuted by oil 



or dirt getting between the spring and the 
screw, as the spring B only forms a part of the 
electrical circuit when in contact with both the 
cam C and the screw A. 

Another form of commutator for a four-cyl¬ 
inder motor is illustrated in Figure 110, which 
has a rotary spring contact-maker A, which 
engages successively with the heads B of the 
screws C. The screws are spaced equidistant 
around the fiber ring D, which also forms the 
case of the commutator, and are held in position 



The Automobile Handbook 247 

by the locknuts E. The spring contact-maker 
A is attached to a hub F on the cam shaft of 
the motor. The time or point of ignition may 
be varied by moving the commutator case about 
its axis by means of a rod attached to the 
arm G. 

Figure 111 shows two commutators of very 
similar construction. The one at the left in the 
drawing is for a two-cylinder motor, and has 
fiat spring-steel contact-makers. The commu¬ 



tator shown at the right of the drawing is for 
a four-cylinder motor and instead of having flat 
spring contact-makers, it has either carbon or 
copper contact-brushes, which are held against 
the commutator by short coil springs in the in¬ 
sulated bushings located around the periphery 
of the commutator case. The commutator is 
made of vulcanized fiber with a short brass or 
or copper segment, which is grounded to the 
cam shaft as shown. 







248 The Automobile Handbook 

The forms of commutators illustrated in the 
drawings may be constructed for use with a 
motor of any number of cylinders, by increas¬ 
ing or decreasing the number of contact-mak¬ 
ers located around the commutator. 

Compression. Normal compression in any 
given design of motor would be the compres¬ 
sion (cold) fixed by the designer by the rela¬ 
tion of the sweep of the piston to the clearance 
space. Normal compression is not the same, as 
measured in pounds per square inch, in all mo¬ 
tors. The normal compression as against loss 
of compression would be evident to a motorist 
in the act of cranking. Were the compression 
to become abnormal, as a result of carbon de¬ 
posit, it would be rendered manifest by knock¬ 
ing on a gradient, or by way of pre-ignition. 

Limits of Compression. With gasoline vapor 
and air, the compression cannot be raised much 
above 85 pounds per square inch, but with 
the heavier fuels, such as kerosene, a com¬ 
pression as high as 250 pounds per square inch 
has been used economically. It has been the 
advantages of high compression that has turned 
the designer of automobiles toward the heavier 
fuels; but, with the increase of compression, 
there are many troubles in regard to loss of 
power and increased fuel consumption, owing 
to the wear of the valves, pistons and cylinders, 
which produces a loss in compression and ex¬ 
plosive pressure, and a waste of fuel by leakage. 

Compression, How to Calculate. The com- 


The Automobile Handbook 


249 


pression in atmospheres of a motor may be read¬ 
ily found by dividing the cubic contents of the 
piston displacement by the cubic contents of 
the combustion chamber in cubic inches, and 
then adding one to the result. 

To ascertain the compression in atmospheres 
of a motor, when the cubic contents of the com¬ 
bustion chamber are known: Let S be the 
stroke of the piston in inches and A the area of 
the cylinder in square inches. If C be the con¬ 
tents of the combustion chamber in cubic inches 
and N the required compression in atmospheres, 
then 

S'XA 

N = - +1 

C 

Example: Find the compression in atmos¬ 
pheres of a motor of 4-inch bore and 6-inch 
stroke, whose combustion chamber has a capac¬ 
ity of 18 cubic inches. 

Answer: Six multiplied by 12.56 equals 
75.36, which divided by 18 gives 4.19, and 4.19 
plus 1 equals 5.19, or the compression in at¬ 
mospheres required. One atmosphere = 14.75. 

If it is desired to ascertain the compression 
in atmospheres of a motor, the combustion 
chamber of which is of such shape that its di¬ 
mensions cannot be accurately calculated, its 
cubic contents may be found by filling the com¬ 
bustion chamber with water, and after remov¬ 
ing the water, ascertaining its weight in ounces, 



250 The Automobile Handbook 

and then multiplying the result by 1.72. This 
gives the capacity of the combustion chamber 
in cubic inches. The compression of the motor 
can then be readily calculated from the for¬ 
mula given herewith. 

Compression, How to Test for Leaks in. To 
discover if there are any leaks in the compres¬ 
sion of a gasoline motor, a small pressure gauge 
reading up to 75 pounds should be fitted into 
the spark plug opening in the combustion 
chamber by means of a reducing bushing. When 
turning the starting crank of the motor slowly 
the gauge should indicate at least 60 pounds 
per square inch if the compression is in good 
condition. 

To test for leaks, fill a small oil can with 
soapy water and squirt round every joint where 
there may be a possible chance for leakage. Get 
an assistant to turn the crank and watch for 
bubbles at the joints. 

If the joints are all tight, next examine the 
condition of the admission and exhaust-valves 
and if either of them needs regrinding, it 
should be done, first with fine emery powder 
and oil, then finished with tripoli and water. 

When the valves have been ground to a per¬ 
fect fit, if the compression still leaks, the pis¬ 
ton rings should be examined, as the trouble 
will be found to be with them. 

Condenser, Use of. A condenser is used in 
connection with a Rumkorff, or jump-spark 
form of induction coil to take up or absorb the 


The Automobile Handbook 


251 


static charge of electricity, occasioned by the 
self-induction, or electrical reaction in the pri¬ 
mary winding of the coil upon the breaking of 
the battery circuit by the interrupter or vibra¬ 
tor. This static charge is given up or dis- 



Fig. 112 
Condenser 


charged into the primary winding of the coil 
along with the battery current upon the closing 
of the circuit, thus intensifying the action of 
the secondary winding of the coil in a great de¬ 
gree. 

By absorbing the static charge of electricity 





























































252 The Automobile Handbook 

the condenser helps to decrease the spark or arc 
between the platinum contact points of the in¬ 
terrupter or vibrator, thereby lengthening the 
life of the platinum contacts by reducing the 
erosive action of the induced current spark. A 
jump-spark coil very often refuses to work 
properly on account of the condenser connec¬ 
tions having become loose. 

The capacity of a condenser is directly pro¬ 
portional to the area of the tinfoil sheets com¬ 
posing it, to the distance between the sheets, 
and to the inductive capacity of the dielectric, 
or separating medium. 

In condenser work it is the custom to cut the 
tin-foil sheets to some convenient rectangular 
shape, as shown in Fig. 112, each one with a 
neck so that all the + sheets can be soldered to¬ 
gether, on one side, and all the — sheets on the 
other. The dielectric paper is cut without 
necks, so that the necks of the tin-foil sheets 
can be readily contacted with each other, in 
such a way, however, that the + sheets will 
not contact with the — sheets at any point. 
The paper is 1 inch wider than the tin-foil, so 
that the paper extends out for % inch all 
around, and beyond the tin-foil. In the illus¬ 
tration the top sheet of paper is removed to 
show the shape of the tin-foil sheets, and it will 
be observed that all the tin-foil sheets are of 
the same size, but they are so turned that the + 
sheets have their necks all to one side, while 
the — sheets have all their necks to the other 


The Automobile Handbook 253 

side. Any number of sheets can be used, with 
the understanding that a sheet of oil-paper will 
be placed between adjacent tin-foil sheets, so 
that the -f- and — sheets will not contact with 
each other at any point. 

If the paper is pierced, or if the + and — tin- 
foil sheets contact with each other, the con¬ 
denser will fail to perform its functions, and it 
sometimes happens that the sheets are punc¬ 
tured in service, thus rendering the condenser 
valueless for the intended purpose until the 
puncture is repaired, to do which requires that 
the fault be found, and a new sheet of paper 
substituted. 

Condensers are made to fit into housings that 
allow of ready application on the instrument 
with which they are used. In many cases it is 
desirable to use a cylindrical form, while in 
others a rectangular outline may be permissible. 
Condensers of unusual form are often made from 
two long strips of tin foil, laid one upon the 
other, and separated by waxed paper or other 
insulating material. The long strip is then 
rolled or folded into the shape that is desired 
and the ends of the foil are attached to the con¬ 
denser terminals. 

A punctured or faulty condenser will cause 
the spark to be very weak and will also cause 
quite violent arcing at the breaker contacts, this 
arcing burning and pitting the contacts until 
they can no longer carry the current. The con¬ 
denser connections must always be secure. 


254 


The Automobile Handbook 


Cooling Systems. The cooling of a gasoline, 
or other automobile engine may seem a simple 
thing to the uninitiated, but in reality it is far 
from that and it is a fact that the deeper one 
goes into it, the more complex the situation be¬ 
comes. 

The cooling of internal combustion engines, 
in which category automobile engines come, is 
divided into two classes, viz., air cooled and 
liquid cooled. There are two reasons for cool¬ 
ing the cylinder walls. One is to permit of 
proper lubrication, and the other is to prevent 
pre-ignition. But it is advisable to allow the 
cylinder to work at as high a temperature as 
the lubricating oil will stand without carboniz¬ 
ing. The nearer the cylinder temperature can 
be kept to 350 degrees the more efficient will 
the motor be, speaking from the thermal stand¬ 
point, while on the other hand, mechanical effi¬ 
ciency may be sacrificed by too high tempera¬ 
tures. Therefore, a balance between the two 
should be established, and this course is usually 
pursued in practice. 

Air-Cooled Automobile Engines. The suc¬ 
cessful air oooling of an engine cylinder de¬ 
pends chiefly on an abundant flow of cool air 
over it. Some cylinders, however, are arranged 
to utilize a more rapid flow than others. Gen¬ 
erally speaking, the designer can take his choice 
between a comparatively plain cylinder surface 
over which a current of air can flow almost un¬ 
checked, and a cylinder with its heat-radiating 


The Automobile Handbook 


255 


surface greatly multiplied by numerous pins, 
deep ribs, or other projections. These projec¬ 
tions increase greatly the radiating surface, but 
tend to obstruct the flow of air, although they 
aid in carrying away the heat. In the latter 
case, the velocity of the air stream does not 
need to be high, provided it is continuous ; while 
in the former case, a constant and abundant 
supply of air is essential. 

Air-Cooling Systems. In modern automobile 
practice two systems of cooling are used—the 
air system and the water system, each of which 
has its adherents. As its name indicates, the 
air cooling system allows the air to strike the 
exterior of the engine cylinder, and thus carry 
off the excess of heat' generated within it. To 
give the radiating surface, required for air 
cooling, the exteriors of the cylinders are either 
grooved or corrugated, or the surface of the cyl¬ 
inder is studded with metal pins or fins, so as to 
present as much surface to the outside air as 
possible. The object in the construction of all 
air-cooled motors is to make their external sur¬ 
faces offer as great a surface to the air as pos¬ 
sible, and to furnish these surfaces with as large 
a supply as possible. A fan is therefore used, 
driven by the engine itself, which constantly 
directs a current of fresh, unheated air upon 
the surface of the cylinder. 

Fig. 113 is a sectional view of a vertical air¬ 
cooled gasoline motor. The radiating ribs cast 


256 


The Automobile Handbook 



AIR-COOLED MOTOR 

Fig. 113 


























The Automobile Handbook 257 

around the cylinder and valve chamber are 
plainly discernible. This motor has a detacha¬ 
ble atmospherically operated admission-valve, 
without packing. The valve and cage may be 
removed by simply removing two nuts. 

Modern forms of air cooling give excellent 
satisfaction regardless of the temperature of the 
outside air. Individual air leads for each cylin¬ 
der insure even cooling. 

Water Circulation. There are two systems 
of water circulation in use for cooling the cylin¬ 
ders of explosive motors: The natural or ther¬ 
mo-siphon system and the forced water circu¬ 
lation. 

In natural or thermo-siphon water circula¬ 
tion the fact that cold water is heavier than hot 
water is taken advantage of. A head of water 
is obtained by placing the tank above the level 
of the cylinder water-jacket, and as the water 
in the jacket is heated by the combustion, the 
cooler water from the tank flows in, forcing the 
heated water in the tank to take its place, and 
in this manner an automatic circulation of wa¬ 
ter is set up. The pipes must be so arranged 
that they offer every facility for the free cir¬ 
culation of the water, the cold water leaving 
through a pipe at the bottom of the tank and 
entering at the lowest point of the cylinder, 
while the hot water leaves the top of the cylin¬ 
der and enters the tank at the side near the 
top. The water circulation, though automatic, 
is very slow, and for this reason requires a 


258 


The Automobile Handbook 



larger body of water to produce as good a cool¬ 
ing effect as a forced circulation. 

In forced circulation a rotary pump is used, 



















































The Automobile Handbook 


259 


the direction of the flow being such that the 
water passes from the pump to the cylinder, 
thence to the radiator, on to the tank, and then 
through the pump again, thus completing its 
circuit. The water in this way gets the maxi¬ 
mum cooling effect from the Radiator, and the 
body of water in the tank is kept cool. On ac¬ 
count of the high speed of a gasoline automo¬ 
bile motor, and the comparatively small amount 
of power required to circulate the water, ro¬ 
tary pumps are much used. As there are no 
valves to get out of order, and high speed is 
obtainable, this type of pump is very suitable 
for automobile use. 

In order that a thermo-syphon system may 
operate successfully, it is absolutely essential 
that the water passages around the cylinders, as 
well as the connections to the radiator, be of 
large capacity and perfectly free from obstruc¬ 
tions. Sharp bends should be avoided in every 
case. 

Overheating—Causes of. Overheating of the 
engine, when not traced to poor circulation, is 
almost always caused by too much gasoline. 
There are, however, many possible causes of 
over rich mixture, some of which on the 
face of them might seem to be causes of lean 
mixture rather than rich. Prominent among 
these latter is too low a gasoline level in the 
float chamber due to the float valve closing too 
soon. The immediate effect of this is to make 
the mixture too lean at starting, and at low 


260 


The Automobile Handbook 


speeds. Starting is therefore difficult, and if 
the auxiliary air valve begins to open at the 
usual motor speed, the mixture will again be 
much too lean. These symptoms, however, un¬ 
less properly interpreted will probably lead the 
owner to increase the gasoline supply, or to ad 
just the spring tension of the auxiliary valve so 
that the latter will not open until quite high 
speed is attained. In other words, he adjusts 
to give a suitable mixture at one speed, and at 
other speeds the mixture is extravagantly over 
rich. It is well not to be too easily satisfied 
with the carbureter’s performance, as it may 
be found that one fault such as the above has 
been imperfectly offset by another fault in the 
other direction instead of the correct adjust¬ 
ment being made where the fault really lies. A 
good carbureter will give a sensibly correct 
mixture at all speeds within the ordinary range 
of the engine. If it fails to do this the thing to 
do is to investigate until the trouble is found. 

Insufficient lubrication increases the friction 
between the piston and cylinder, and so gener¬ 
ates extra heat. Bad or unsuitable oil may 
have the same effect. 

Wear of the cams, tappets and valve stems 
may be the cause of overheating, as it would 
not require much loss from the faces of the va¬ 
rious moving parts that come in contact to 
cause a more or less appreciable difference in 
the operation of the valves, and as this wear 
tends to bring about a later action, it may be 


The Automobile Handbook 


261 


sufficient in the case of the exhaust valve to 
retain the burnt charge considerably < beyond 
the time at which it should be allowed to es¬ 
cape. Where a motor runs at a speed of 800 
revolutions per minute or over, it will be evi¬ 
dent that it is a matter of very small fractions 
of a second. 

Another cause of overheating may be the de¬ 
posit of a fine film of scale on the inside of the 
circulating pipes and radiator. This scale is of 
a mineral nature, and, in addition to being an 
excellent nonconductor of heat, it is deposited 
in such intimate contact with the metal that the 
latter is practically insulated and its radiating 
power entirely lost. 

Overheating—Effects of. The immediate 
effect of overheating is to burn up the oil in the 
cylinders, or crank case. This causes a smell 
of burning, and an ordor of hot metal. There is 
sometimes a slight smoke and the motor will 
make a knocking sound. The cooling water be¬ 
gins to steam, and the car will gradually slow 
down and finally stop. 

The most serious cause of a stoppage on the 
road is overheating, which causes the lubricat¬ 
ing oil to burn up and the piston to expand and 
grip or seize in the cylinder. 

Overheating—Remedies for. As soon as any 
of the above symptoms are noticed: 

The motor should be stopped at once. 

Kerosene should be copiously injected into 


262 The Automobile Handbook 

the cylinders and the motor turned by hand to 
free the piston-rings. 

The parts should then be allowed to cool. 

Do not pour cold water on the cylinder jack¬ 
ets, for fear of cracking them, but pour the wa¬ 
ter into the tank so as to warm the water before 
it reaches the cylinder jackets. 

A simple test in the case of an overheated 
motor is to let a few drops of water fall on the 
head of the cylinder. If it sizzles for a few mo¬ 
ments the overheating is not bad, but if the 
water at once turns into steam, the case is seri¬ 
ous. 

Detach the spark plug or plugs, and turn the 
starting-crank slowly. This draws in cold air 
and cools the inside of the cylinder and the pis¬ 
ton. 

After the parts are cool, it will be advisable 
to put some oil in each cylinder. 

Dalton’s Laws. The relation between the 
vapor tension and the quality of vapor is ex¬ 
pressed by two laws known as Dalton’s laws, 
as follows: 

I. The pressure, and consequently the quan¬ 
tity, of vapor that will saturate a given space 
are the same for the same temperature, whether 
the space contains a gas, or is a vacuum. 

II. The pressure of the mixture of a gas and 
a vapor is equal to the sum of the pressures that 
each would exert if it occupied the same space 
alone. 

If a volatile liquid is added to a gas, and the 


The Automobile Handbook 263 

resulting mixture of gas and vapor is allowed 
to expand so that the pressure remains un¬ 
changed, the volume of the mixture will exceed 
the original volume of the gas. The ratio of 
this new volume to the original volume of the 
gas is equal to the ratio between the combined 
pressure of the gas and vapor, and the pressure 
of the gas alone, had the volume remained con¬ 
stant. 

Deposits in Water Jacket. If the cooling 
water contains lime or alkali, the heating of the 
water in the jacket will cause these solid sub¬ 
stances to be deposited in the cooling spaces. 
This will soon choke any narrow ports and pre¬ 
vent proper circulation, resulting in overheat¬ 
ing, rapid wearing of the valves, and loss of 
power and efficiency. A simple remedy consists 
of the application, at regular intervals, of a di¬ 
lute solution of hydrochloric, or muriatic, acid, 
made as follows: Dilute one part of muriatic 
acid with nineteen parts of water, and, after 
draining the jacket completely, pour in enough 
of the solution to fill the entire cooling space. 
Allow the mixture to remain in the jacket for 
not more than 8 to 12 hours, after which wash 
the cooling space thoroughly by running clear 
water through it. If the solution is permitted 
to remain in the jacket longer than the period 
stated, there is danger that the metal may he 
damaged by the action of the acid. The acid 
will soften and dissolve the lime or alkali, and 
the clean water will remove it from the jacket. 


264 


The Automobile Handbook 


It is generally sufficient to apply this method 
of removing the deposits once every two weeks. 
If neglected too long, the acid will not dissolve 
the deposit. 

Differential Gears. So long as an automo¬ 
bile moves in a perfectly straight path, its two 
driving wheels turn at equal speed, since they 
must cover equal distances in equal periods of 
time, and it would be perfectly allowable that 
the two wheels should be locked together, as 
there would be no relative motion between 
them. The power could be transmitted to 
either one, or to both of them with perfectly 
satisfactory results under these circumstances. 
When, however, a car is to be moved in a curved 
path, as in turning a corner, the driving wheels 
must move at different speeds, since the out¬ 
side one has to cover a longer distance in the 
same time than does the wheel which is on the 
inside of the curve. If the two wheels were 
locked together under these conditions, one or 
both of them would be forced to slip, as the 
speeds transmitted to them would be equal, 
while the distances they are to travel are un¬ 
equal. This difficulty is successfully overcome 
by the use of the differential gear which trans¬ 
mits the power from the change-speed gear to 
the rear axle, or driving wheels of the car. 
Differential gears consist of a set of four or 
more gears attached to the ends of two shafts 
that meet, and are usually in line, so that 
both are rotated in the same direction. But, if 


The Automobile Handbook 


265 


either meets with extra resistance it may rotate 
more slowly than the other, or may stop alto¬ 
gether. 

These gears are used on the driving axles 
of automobiles. The axle is made in two parts, 
with a gear on the end of each, where the parts 
come together. Other gears mesh with both 
these axle gears, and are driven from the engine 
by a sprocket and chain, or by bevel gears and 
shaft. These gears turn the axle, but permit 



Bevel Gear Differential With Bevel Driving Gear 
and Pinion 


its two parts to turn in respect to each other 
so as to allow the automobile to go around a 
corner without causing the wheels to slide, or 
skid. The rear wheels are each fixed to a half 
of the rear axle, and both receive power, 
hence it is necessary to allow one wheel to turn 
at a different speed from the other, and this 
is accomplished \y means of the differential 
gear. 


















266 The Automobile Handbook 

Bevel Gear Differential. Fig. 117 shows a 
bevel gear differential in which A and B are the 
two halves of the rear axle, which is divided at 
its center. One of the driving wheels is carried 
on A, and the other one on B, while the inner 
ends of the two half axles are each fitted with 
bevel gear wheels C and D. Meshing with 
these two bevel gears are two, three or four 
bevel gears, two of which are shown at E and 
F. These pinions are supported on radial studs 
which project inwardly from the casing. Upon 
this casing are sprocket or bevel gear teeth 
which are driven from the engine. The teeth of 
each pinion, E and F are at all times in mesh 
with the teeth of both the bevel gears C and D 
on the axle. When the car is in operation, the 
chain or bevel drive revolves the case contain¬ 
ing the pinions, and the power is transmitted 
through the teeth of the pinions E and F to the 
teeth of the gears C and D and thence to the 
axle and wheels. So long as the vehicle travels 
in a straight line, the pinions act -as stationary 
driving members, and have no occasion to re¬ 
volve, as the two halves of the axle and their 
gears are moving at equal speeds. They merely 
revolve with the frame. The same teeth of the 
bevel pinions and gears are in contact so long 
as a straight path is traversed. When, however, 
the car is steered in a curve and different veloc¬ 
ities are required in the drivers and the bevel 
gears with which they are connected, the pin- 


The Automobile Handbook 


267 


ions no longer act as fixed driving members, 
but each turns upon its stud and allows the 
necessary relative motion between the two bevel 
gears, and at the same time they continually 
transmit power to the two ends of the axle be¬ 
cause they are always in mesh with each other. 
This compensating action may continue indefi¬ 
nitely through any amount of variation be¬ 
tween the driving wheel rotation, because one 



Fig. 116 

Bevel Gear Differential Connected to Sprocket 


tooth of the pinions comes into play as fast as 
the preceding one disengages with the bevel 
wheels on the shaft. Fig. 116 presents a larger 
view of the bevel gear differential, the two 
gears on the rear axle being shown as secured 
to the shaft, and to a sleeve on the shaft. The 
differential employed here has three bevel pin¬ 
ions turning on radial studs, which are secured 
to the arms of a spider at their inner end. A 
differential bevel gear, although most extern 


















268 


The Automobile Handbook 


sively used, is open to the objection that the 
bevel gears impose an end thrust upon the two 
halves of the mainshaft on rear axle. This has 
led to the design of differentials in which only 
spur gears are used. 



Fig. 117. 

Bevel Gear Differential. 


Bevel Gear Differential. Fig. 118 shows 
• a semi-sectional view of the bevel differential 
gear. The engine shaft carries a bevel gear 
wheel shown in section at a. This gear meshes 
with the large bevel gear b, on the differential 
gear case c. On the inside of this gear case 
are carried a number of small bevel gears, one 
of which is shown in section at d. These are 
free to turn on the studs that hold them to the 
gear case. These gears in turn mesh with bevel 
gears e and f, on the ends of the half axles. 

The principle governing the action of the 
bevel gear differential is similar to that of the 





The Automobile Handbook 


269 


spur gear differential. When the two bevel 
gears e and f on the half axles meet with the 
same resistance, the small bevel gears d do not 
turn on their bearings; but when the movement 
of one of the gears e or f is resisted more than 



that of the other it lags behind, causing the 
small bevel gears d to turn on their axles suffi¬ 
ciently to equalize the resistance. 

Spur Gear Differential. In the spur dif¬ 
ferential, bevel gears are replaced by gears of 























270 The Automobile Handbook 

the spur type, as shown in Fig. 119, a large 
spur gear being secured to each half axle, as 
shown at A and B, exactly as are the bevel 
gears. A double set of spur pinions, E and F, 
having their bearings in the frame, revolve 



upon axes parallel with the axle. For each 
bevel pinion is substituted a pair of spur gears, 
E and F, which mesh with each other, and at 
the same time each one of them is in mesh with 
one of the large gears. The combination of the 


























The Automobile Handbook 271 

motion of each pinion of the pair upon its gear, 
and the motion of the pair upon each other 
produces the same effect as the use of a bevel 
pinion. When the vehicle is rounding a curve, 
one rear wheel moves less rapidly, causing the 
pinions with which it is geared to revolve upon 
their bearings, and thus compensate for the in¬ 
creased resistance. 



Pig. 120 

Sectioned and Side View of Bevel Gear Differential 


Testing Differential Gears. The differen¬ 
tial gear should be tested with a view to locat¬ 
ing any wear or side play. This may be done 
by jacking up the rear axle and shaking one 













272 


The Automobile Handbook 


wheel forward and backward while the other 
is held stationary., and noting how far the 
wheel must be turned before the movement is 
taken up by the flywheel of the engine. Any 
noticeable play will generally be found either 
in the center pinions of studs of the differential 
gear, in the large and small bevel gears, in the 
clutch sleeve, or in the universal joints. The 
differential gear, and live axle of modern cars 
seldom give trouble if kept properly lubricated, 
and the car’s mileage should run up into many 
thousands before any considerable amount of 
play is evident. The joint pins of the propeller 
shaft may become loose through wear, in which 
case a knocking noise in the transmission gear 
will indicate the cause and location of the 
trouble. These pins may be readily replaced 
with new ones at small cost. If the play is 
found in the bevel gears, the small gear should 
be adjusted to mesh deeper with its larger mate. 
This may be done by means of the adjustable 
locking ring or by inserting a washer of the 
proper thickness. It may be found, however, 
that no adjustment is necessary, and a thor¬ 
ough cleaning with gasoline to remove all oil 
and grease will be all that is required. The 
case should then be refilled with the quantity 
of oil and grease recommended by the manu¬ 
facturers. 

Distributers. Instead of employing a sepa¬ 
rate spark coil for each cylinder of a multi¬ 
cylinder engine, the primary circuits of which 


The Automobile Handbook 273 

are made and interrupted in rotation, a device 
known as the distributer may be used, which 
permits of any number of cylinders being 
sparked from a single coil. In magnetos de¬ 
signed for jump spark ignition of multi-cylin¬ 
der engines the distributer forms part of the 
magneto and is rotated by it. The distributer 
is nothing more than a timer of secondary cur¬ 
rent, and generally consists of a cylindrical shell 
of insulating material, upon the inside of the 
cylindrical surface of which equidistant metal¬ 
lic segments in number equal to the motor cyl¬ 
inders are inserted. A conducting arm rotat¬ 
ing upon a shaft concentric with the insulated 
shell carries a brush, which successively makes 
contact with the segments. The arm is in per¬ 
manent electrical connection with the free sec¬ 
ondary terminal of the coil, and each one of 
the segments is wired to the spark plug of a 
cylinder. 

In the case of four-cylinder motors the 
moving arm is geared at one-half the speed of 
the motor, thus making contact for each cyl¬ 
inder once in each two revolutions or complete 
cycle. 


274 


The Automobile Handbook 


Dynamometer. A dynamometer is a form of 
equalizing gear which is attached between a 
source of power and a piece of machinery when 
it is desired to ascertain the power necessary to 
operate the machinery with a given rate of speed. 

Electricity, Forms of. Electricity or electri¬ 
cal energy may be generated in several ways— 
mechanically, chemically and statically or by 
friction. By whatever means it is produced, 
there are many properties which are common 
to all. There are also distinctive properties. 
The current supplied by the storage battery 
will flow continuously until the battery is prac¬ 
tically exhausted, while the current from a dry 
battery can only be used intermittently; that is, 
it must have slight periods of rest, no matter 
how short they may be. 

The dynamo or magneto current is primarily 
of an alternating nature, or one which reverses 
its direction of flow rapidly. In use, this alter¬ 
nating current is changed into a direct or con¬ 
tinuous current flowing in one direction only, 
by means of a commutator. Any of the forms 
described are capable of igniting an explosive 
charge in a motor cylinder, but the static or 
frictional form of electricity is not used for this 
purpose on account of its erratic nature. 

Electric Apparatus—Care of. The following 
instructions apply particularly to electric ap¬ 
paratus in connection with the operation of au¬ 
tomobiles. Look over the electrical plant and 
replace worn wires with new. Clean out the 


The Automobile Handbook 275 

timer with gasoline and lubricate with light oil. 
The magneto need not be taken apart, as it will 
probably only need a little surface cleaning, a 
few drops of oil, and the amateur had better 
not meddle with its internal mechanism. The 
storage battery should be examined, and if the 
brown deposit collects in any quantity at the 
bottom, the electrolyte should be poured out 
into a glass bottle, and the battery washed out 
with clear water (rain water preferred). Clean 
the top of the battery and make it a point to 
keep it clean and free from acid. Clean the 
terminals of any corrosion, and see that the air 
vents are not clogged up. If the accumulator 
has been neglected, either in the electrolyte 
having been allowed to get below the proper 
level or in not giving it the regular monthly 
“charge/’ it may get a bad case of sulphating. 

To get the battery into its normal condition, 
empty out the electrolyte and wash the case 
thoroughly with soft water. Pour in only 
about seven-eighths of the acid solution and fill 
up with distilled water to cover the top of the 
plates. The battery should then be charged 
with a low current until the plates are restored 
to their normal condition. If very badly sul- 
phated, the white coating should be washed off 
with a rag, and in case this fails to remove it, 
scraping must be resorted to. If the electro¬ 
lyte is not sufficient to cover the top of the 
plates, fill up with distilled water so that the 
liquid will just cover them. The specific grav- 


276 The Automobile Handbook 

ity of the electrolyte should not be less than 
1.150, and, although varying somewhat, a hy¬ 
drometer reading of 1.250 is recommended. 
This is approximately 1 part of sulphuric acid 
to 4% parts of water, which will be found suf¬ 
ficiently accurate if no hydrometer is at hand. 
If the electrolyte should test lower than the 
first figure, add pure sulphuric acid until the 
1.250 mark is reached. 

In case the plates are broken down or 
“buckled,” or if the paste has dropped out of 
the pockets of the grids, the accumulator should 
be sent to the manufacturers for repair. In 
some accumulators the liquid is not used, but a 
jelly made of silicate of sodium and dilute 
sulphuric acid takes its placer. If your battery 
is of this type, it is well to remember that the 
jelly must be kept moist on the top, and as the 
emulsion becomes dry a little water should be 
added to replace that which is lost through 
■ evaporation. 

The contact points of the coil will probably 
require adjusting. This is very easily accom¬ 
plished by trimming up the points with emery 
paper. Do not rub away the metal unneces¬ 
sarily, only removing enough to true the points 
so that they make a good contact. In adjust¬ 
ing the vibrator, remember that a light tension 
is much better than a stiff tension. A light 
flexible vibration with a moderately high- 
pitched buzzing note will not only give a better 
spark, but will keep the points in better shape. 


The Automobile Handbook 277 

A heavy tension will make the coil less respon¬ 
sive and will pit the contact points and exhaust 
the battery more quickly. As a coil will ren¬ 
der the most efficient service only when the vi¬ 
brators are adjusted as nearly alike as possible, 
a special ammeter is often used to determine 
the current consumption of each unit. The am¬ 
meter should show a reading of 6-10 amperes. 

Electric Horsepower. See Horsepower . 

Electric Ignition. See Ignition. 

Electric Lighting and Starting. See Start¬ 
ing and Lighting Systems. 

Electric Lighting and Starting. See last part 
of this volume. 

Electromotive Force, Definition of. The 

cause of a manifestation of energy is force; if 
it be electric energy in current form it is called 
electromotive force. An electromotive force 
or pressure of one volt will force one ampere 
through one ohm of resistance. 


278 


The Automobile Handbook 

Engines, Internal Combustion. 


Engine—Construction of. An automobile 
engine should answer the following require¬ 
ments in order to meet the demands of the mo¬ 
tor user: It must be of light weight in propor¬ 
tion to its horse power, so that as large a pro¬ 
portion of its power as possible may be avail¬ 
able for propelling the useful load, and but lit¬ 
tle demanded to move its own weight; it must 
be compact, in order that it shall not occupy 
too large a proportion of the available room of 
the car; it must operate without undue noise 
and vibration; it must be fully enclosed as a 
protection against the weather, and still it must 
be so located as to be easily accessible for in¬ 
spection, oiling and repairs; its operation must 
be automatic 'for considerable periods of time, 
as regards cooling and lubrication; it must be 
capable of running very slowly, or very fast at 
will, and of developing little, or much power; it 
must be supported upon the car in such a man¬ 
ner that its power may be most readily and 
efficiently transmitted to the driving wheels, 
and it must further be carried upon springs so 
that the jar and shock-from the road shall not 
be transmitted to it. 


Explosive Motors. Explosive motors are of 
three forms, known as stationary, marine and 
automobile. Their general characteristics are 


The Automobile Handbook 279 

implied by their various designations. The sta¬ 
tionary motor may be either vertical or hori¬ 
zontal. Marine motors, designed for applica¬ 
tion to boats, are almost invariably vertical. 
Automobile motors are of comparatively recent 
introduction and of great variety, the aim of 
the designers being to secure the maximum of 
power and minimum of weight. They also 
may be vertical or horizontal. 

These three forms may be again divided into 
two-cycle and four-cycle types. In the former 
an explosion occurs at every revolution. In the 
latter there is an explosion at every alternate 
revolution. 

Explosive motors are dependent for success¬ 
ful operation on two things: First, a charge of 
gas or vapor, mixed with sufficient air to pro¬ 
duce an explosive mixture, and second, a 
method of firing the charge after it has been 
taken into the combustion chamber of the 
motor. 

When coal gas is used the supply is taken 
from the main and mixed directly with the nec¬ 
essary proportion of air. When gasoline is 
used, air is mixed with it in the correct pro¬ 
portion by carbureting devices. 

After the charge of gas and air has been 
taken into the cylinder it is compressed, as will 
be shown later, by the action of the motor itself 
and then fired, usually by an electric spark 
actuated by the motor, but sometimes by the 
use of a tube screwed into the cylinder and 


280 


The Automobile Handbook 



Fig. 121 



















































The Automobile Handbook 


281 


Internal Combustion Automobile Engine. 1, Oil 
Valve Lever. 2, Oil Valve Adjustment. 3, Oil 
Valve Lifter. 4, Oil Valve Slot. 5, Oil Tank 
Cover. 6, Water Jacket. 7, Oil Tank. 8, Oil 
Valve Spring. 9, Oil Valve Plunger. 10, Oil. 11, 
Oil Gauge Glass. 12, Oil Valve. 13, Oil Feed 
Window. 14, Water Inlet. 15, Cylinder Joint. 
16, Cylinder Wall. 17, Crank Case Breather. 
18, Oil Feed Pipe. 19, Connecting Rod Bear¬ 
ing. 20, Crank Pin. 21, Rod Bearing Bolt. 
22, Oil Scoop. 23, Crank Shaft Timing Gear. 
24, Crank Case. 25, Oil Lever Overflow. 26, 
Crankcase Oil. 27, Oil Drain Cock. 28, Cam 
Shaft Timing Gear. 29, Cam Shaft Plate. 30, 
Cam Shaft. 31, Cam Shaft Housing. 32, Ex¬ 
haust Outlet. 33, Gasoline Pipe to Carburetor. 
34, Carburetor Priming Lever. 35, Carburetor. 
36, Throttle Lever Rod. 37, Gasoline Adjust¬ 
ment. 38, Valve Lifter Rod. 39, Valve Stem 
Adjustment. 40, Fibre in Valve Plunger. 41, 
Cylinder Space. 42, Valve Spring. 43, Ex¬ 
haust Pipe. 44, Connecting Rod. 45, Piston. 
46, Wrist Pin Set Screw. 47, Oil Groove in 
Piston. 48, Wrist Pin. 49, Exhaust Manifold. 
50, Manifold Clamp Nut. 51, Intake Manifold. 
52, Intake Passage in Cylinder. 53, Valve Stem. 
54, Valve Head. 55, Valve Opening, Seat and 
Face. 56, Piston Rings. 57, Combustion Space. 
58, Valve Pocket. 59, Priming Cup. 60, Valve 
Cap. 61, Water Outlet Header. 63, Valve Cap. 


The Automobile Handbook 


282 





Fig. 122 

Front and Side View of Section Through Four Cylinder Automobile Engine 























































































































The Automobile Handbook 


283 


heated from the outside, the heat, of course, 
being communicated to the gas. The resulting 
explosion operates the motor. 

The principal parts of a four-cycle explosive* 
motor are the cylinder, the piston, the piston 
rings which fit into grooves in the piston: two 
sets of valves, one to admit the charge and the 
other to permit it to escape after the explosion; 
a crank shaft and connecting rod which con¬ 
nect it with the piston head, and a flywheel, 
whose presence insures steady running of the 
motor, and whose further functions will be 
better understood as the description proceeds. 
In the two-cycle form of motor there is really 
but one valve, the exhaust and admission-ports 
being covered and uncovered by the piston it¬ 
self. 

All of the parts referred to are of the motor 
proper. Other parts, which are separate from 
the motor but on which its operation depends, 
are the carbureter, which supplies the charge 
of gasoline vapor and air for a gasoline motor, 
or a mixing chamber for mixing air and gas in 
the case of a gas motor, and the batteries and 
other parts of the electrical ignition device. 

A part which has no connection with the 
actual running of the motor but with which 
practically all are fitted is the muffler, whose 
purpose is to deaden the sound of the explo¬ 
sion. 

The cylinders of all except very small motors 
are as a rule partly encased in a chamber 


i a' 


284 



The Axfaspmobile Handbook 


through which water is circulated, the object 
of this being to keep the cylinder cool. 



Fig. 123 

Section Through Six Cylinder Long Stroke Engine 


Offset Crankshafts. The practice of off¬ 
setting the crankshaft in automobile motors is 
rapidly gaining converts, and there are numer¬ 
ous examples of offsetting to be seen at the 



















The Automobile Handbook 


285 


present time. In this scheme, it will hj^ roinem- 
bered, the crankshaft is not set in the plane of 
the middle of the cylinders. In othOr words, 
the crankshaft is set slightly to “one side. The 
exact amount of this offset seems to be variable 



with different designers, but the object is al¬ 
ways the same. When the piston is in the po¬ 
sition of maximum compression involving the 
ignition and flame propagation, it is the idea 
to have the connecting rod in the vertical po- 

















286 jf/t-e Automobile Handbook 

sition. The force of the explosion will then 
come on the connecting rod endwise and the 
piston will not be pressed unduly against the 
cylinder walls. 

Offset Crank Shaft Engine—Timing the 
Valves. To time the valves of an engine hav¬ 
ing an offset crankshaft, the inclination of the 
axis of the connecting rod must be taken into 
account. As Figure 124 shows, the connecting 
rod is vertical, and if the shaft center were not 



Fig. 125 

Diagrams Showing the Four Positions of the Offset 
Crankshaft 


to one side, the flywheel would be marked at 
the exact center of the upper face, namely, at C. 
In the case where the center is set over, the rod, 
when in a vertical position as at G is not at 
the end of the stroke. If the flywheel were 
marked at C it would not indicate correctly the 
lower dead center. This does not appear until 
the three centers, piston pin, crank pin, and 
crankshaft are in line, as shown by the line 
D E F. The flywheel should be marked at this 


















The Automobile Handbook 287 

point, and the mark may be on a vertical line 
through the crankshaft center or on a diagonal 
as the line just indicated. In the latter in¬ 
stance, the mark for the lower center would be 
at H. 

Similarly, the upper dead center, if marked, 
would be at a vertical point above the shaft 
center as C, but would assume a different posi¬ 
tion, located on a diagonal, as at A, on the cen¬ 
ter line ABE. 

Of course, in actual timing, the upper and 
lower centers are not used, as good practice de¬ 
crees an overlap for the valve action, but they 
have been used as an illustration in this case be¬ 
cause their use simplifies the matter. 

In Fig. 125, the actual marking of a fly¬ 
wheel is shown for a complete cycle. In this the 
angles selected follow the best modern prac¬ 
tice, being as follows: Inlet opens at 8 degrees 
past the upper center, and closes at 26 past the 
lower center, giving an inlet opening, total, of 
198 degrees. Exhaust opens at 46 degrees be¬ 
fore the lower center and closes at 5 past the 
upper. This gives the whole angle for the ex¬ 
haust, 231 degrees on the crankshaft. 

As shown, the markings are put on the fly¬ 
wheel directly above the center of the crank¬ 
shaft, but the offset is taken into account. 

Pistons. The piston used in a gasoline motor 
cylinder is of the single-acting or trunk type. 
It is made of an iron casting which is a good 
working fit in the cylinder. Around the upper 


288 


The Automobile Handbook 


end of the piston three or four grooves are cut, 
and in these grooves the piston-rings fit. The 
rings are made of cast iron, and the bore of the 
ring being eccentric to its outer diameter, there 
is a certain amount of spring in them, and so 
pressure is caused against the cylinder wall, 
preventing any of the expanding gases passing 
the piston. 

Piston Materials. Until recently it has been 
the universal practice to make internal combus¬ 
tion engine pistons of cast iron for the reason 
that this material does not warp under heat to 
such an extent as does steel. The principal 
objection to cast iron has been its comparatively 
high weight, this weight being necessary because 
of the lack of great strength in the metal. It is 
a well known fact that cast iron is very brittle. 
With the advent of the modern high speed en¬ 
gine, experiments were conducted with steel pis¬ 
tons because of the fact that they allowed of 
lighter construction with equal strength. Steel 
pistons have done satisfactory work, but are very 
high in production cost, and this has prevented 
their general introduction. 

The necessity for reducing the weight of the 
reciprocating parts has more recently led to the 
introduction and use of pistons made from alloys 
of aluminum, which, of course, gives the desired 
reduction in weight. The fit of the piston in the 
cylinder cannot be so tight when cold as with 
cast iron or steel, but as soon as the engine has 
run a few moments, the expansion due to heat 


The Automobile Handbook, 289 

allows the piston to fit close enough for all prac¬ 
tical purposes. These pistons are now fitted in 
many makes and models of stock cars and may 
be fitted to cars already in use. 

Piston Displacement. The piston displace¬ 
ment of a motor is the volume swept out by the 
piston, and is equal to the arp/„ of the cylinder 
multiplied by the stroke ofcVthe piston. The 
expression, cylinder volume, is sometimes con¬ 
founded with the term piston displacement. 
This is erroneous, as the cylinder volume is 
equal to the piston displacement, plus the com¬ 
bustion space in the cylinder head. 

Pistons, Length of. For vertical cylinder 
motors the length of the piston should not on 
any account be less than its diameter, while a 
length equal to one and one-quarter or even 
one and one-third diameters is better. For mo¬ 
tors with horizontal cylinders the length of the 
piston, in any case, should not be less than one 
and one-third diameters, and if possible one 
and one-half diameters or over. 

Piston Position. There is nothing more con¬ 
fusing to many motorists—not only to the be¬ 
ginner, but to many who are proficient in the 
general care and operation of their motor cars 
—than the relative various positions, in a four¬ 
cycle engine, of the four pistons on any of their 
four cycles of compression, work, explosion, 
and exhaust, this being the order of the cycles. 

In the following illustrations the pistons are 
shown as they are usually placed in relation to 


290 


The Automobile Handbook 










m? 






w«w» 




—-> 



11 



• 

M 



■ ::: ; - 



« 












V 



' v 


I;. : • 


Fig. 127 













































































































291 


The Automobile Handbook 





mr* 



■. ' ■ ' 


W3 

. \ a 

' 

. 

• 

Z 3 

ii 


Fig. 128 



Fig. 129 




































































































































































292 The Automobile Handbook 

one another. That is, pistons 1 and 4 are at 
the top of their strokes when pistons 2 and 3 
are at the bottom, and, obviously, vice versa. 
The figures over the pistons in each diagram 
represent their order of number, counting from 
either end of the engine. 

In Fig. 126, cylinder I is ready to descend 
on its intake\^ekd—having finished its ex¬ 
haust stroke—aiud cylinder 4 is ready to de¬ 
scend on its working stroke—having finished 
its compression stroke. Cylinders 2 and 3 are 
ready to move on their up strokes, No. 2 on its 
compression, having finished its intake, and 
No. 3 on its exhaust, having finished its working 
stroke. The results are that the pistons are 
brought into the positions shown in Fig. 127. 
This means that cylinder No. 1, having com¬ 
pleted its intake downward stroke, is ready for 
its compression up stroke; No. 2 has moved up 
on compression and is ready to go down on 
work; No. 3 has finished exhausting and is 
ready for intake and No. 4 has finished the 
work stroke and is ready to move up on ex¬ 
haust. Piston No. 2, having completed its work 
stroke, the pistons are brought back to the po¬ 
sitions shown in Fig. 126, but with an altered 
condition of the cycle represented by each, as 
shown in Fig. 128. The pistons are now ready 
to move to the positions shown in diagram 2, 
with an altered cycle condition. Cylinder No. 
1 moves down on work; No. 2 up on exhaust; 


The Automobile Handbook 293 

No. 3 up on compression and No. 4 down on in¬ 
take, see Fig. 129. 

When the cycle of each has been completed, 
from the above starting points of No. 1, ex¬ 
haust ; No. 2, intake; No. 3, work, and No. 4, 
compression, the pistons are then back not only 
in the position of Fig. 126, but with the same 
condition of cycles. ./ 

This explanation has been in the order of the 
cylinder numbers, but the effect of each cycle 
of each cylinder will be easier trkt A if it be 
remembered that the order in which the cylin¬ 
ders work is: Cylinder 1, then cylinder 3, then 
cylinder 4, and then cylinder 2, and then repeat 
indefinitely. From this and the above illustra¬ 
tions it will be easily understood that as piston 
No. 1 goes down on its work stroke, No. 3 
comes up on compression stroke, and is then 
ready for the work, which is a down stroke 
bringing No. 4 up on compression. No. 4 then 
goes down on work and brings No. 2 up on com¬ 
pression, then it goes down on work and brings 
No. 1 up on compression for the repeating of 
cycles. This shows that each synchronized pair, 
1-4 and 2-3, always have one cycle between them 
as they move together, either up or down. 

Piston-Rings. To ensure proper compression, 
it is absolutely essential that the piston-rings 
should be kept lubricated; consequently when 
the motor has been idle for some time, the 
compression at the start is often poor. Any fail¬ 
ure in the lubrication while running will, of 


294 The Automobile Handbook 

course, have the same effect, such, for example, 
as in the case of overheating, or when the sup¬ 
ply is intermittent. Sometimes the piston- 
rings get stuck in their grooves with burnt oil, 
through overheating, and the compression es¬ 
capes past them. Thorough cleaning with kero¬ 
sene, and fresh lubricating oil will settle the 
matter. In motors where the rings are not 
pinned in position, the slots may work round so 
as to coincide. ./In this case they will have to be 
moved around. Sometimes burnt oil may, ap¬ 
parently, have the opposite effect on piston- 
rings, for by causing the piston to grip in the 
cylinder, it will produce considerable resist¬ 
ance, and the operator might erroneously think 
in consequence that his compression is good. In 
every case, after a long run, a little kerosene 
should be injected into the cylinders to clean 
the rings. 

Piston-Rings—Method of Turning. A pat¬ 
tern should be made from which to cast a blank 
cylinder or sleeve with two projecting slotted 
lugs on one end to bolt same to face plate of 
lathe. This blank should first be turned off out¬ 
side to the required diameter, making it, of 
course, sufficiently larger to allow for the cut 
in the rings, after cutting from the blank. The 
blank should then be set over eccentric suffi¬ 
ciently to allow the thick side of the rings to ba 
twice the thickness of the thin side after turn¬ 
ing. The inside of the blank can then be bored 
out, and the rings cut off to the exact thick- 


The Automobile Handbook 295 

ness required with a good sharp cutting off tool. 
A mandrel or arbor should be made with two 
cast iron washers or collars to tit it, one fas¬ 
tened to the mandrel and the other loose, with 
lock nut on mandrel with which to tighten up 
the loose collar. After the rings have been 
sawed open and a piece cut out the required 
length, they can be placed on a collar or ring 



FOUR-C YCLE MOTOR DIAGRAM 

" Fig. 130. 

about 1-32 to 3-64 of an inch larger than the 
cylinder bore, and slipped on to the mandrel one 
at a time, of course, with the loose collar and 
nut off the same. The loose collar and nut can 
then be put on the mandrel, the ring clamped 
tightly between the two collars, the mandrel 
put in the lathe and the ring turned off, without 
leaving any fins or having to cut the ring off 
afterward as is done in many cases. This is the 
only way in which a perfectly true ring can be 
made. 





















296 


The Automobile Handbook 


Four-Cycle Motor. Fig. 130 furnishes two 
sectional views of a four-cycle type of motor 
with some of the parts removed, as in Fig. 121. 
It shows a cylinder C, admission-valve A, a 
piston P, and exhaust-valve E. 

The left-hand view shows the piston P about 
to suck in a charge of vapor, by the same 
method as previously described, through the 
admission-valve A into the cylinder C. The suc¬ 
tion continues until the piston P reaches the 
position shown in the right-hand view. Then 
the piston returns until it again arrives at the 
position shown in the left-hand view, compress¬ 
ing the charge of mixture during this operation. 
Just before the piston arrives at the end of its 
travel in this direction, the charge of vapor., 
now under compression, is ignited by the 
method previously explained and its expansion 
forces the piston back to the position shown in 
the right-hand view. When the piston has, for 
the second time, reached the position shown in 
the right-hand drawing, a mechanical device 
opens the exhaust-valve. The exhaust-valve 
remains open until the piston has again arrived 
at the position in the left-hand view. Then it 
closes, the piston again commences to draw in 
a charge of vapor and the cycle of operation 
of the motor is repeated. 

Four-Cycle Motor, Operation of. A four¬ 
cycle motor has only one working stroke or im¬ 
pulse for each two revolutions. During these 


The Automobile Handbook 29 ? 

two revolutions which complete the cycle of 
the motor, six operations are performed: 

1. Admission of an explosive charge of gas, 
or gasoline vapor and air to the motor-cylinder. 

2. Compression of the explosive charge. 

3. Ignition of the compressed charge by a 
hot tube, or an electric spark. 


J 



Pig. 131 


Four-Cylinder Engine 

4. Explosion or extremely sudden rise in the 
pressure of the compressed charge, from the in¬ 
crease in temperature after ignition. 

5. Expansion of the burning charge during 
the working stroke of the motor-piston. 

6. Exhaust or expulsion of the burned gases 
from the motor-cylinder. 





























298 The Automobile Handbook 

Two-Cycle Motor. The foregoing outline of 
the functions of the parts of the motor prepares 
us for a description of the two-cycle form of 
motor. This particular form of motor draws 
in a charge of gas or vapor, compresses it, fires 
it and discharges the product of combustion or 
burned gases while the crank makes but a sin¬ 



gle revolution, and while the piston makes one 
complete travel backward and forward. 

Fig. 132 shows two sectional views—that is 
to say, views of the motor cut in two, longi¬ 
tudinally—of the principal parts of a two-cycle 
motor. Other parts, such as the crankshaft, 
connecting rod and flywheel, are omitted to 
avoid confusion. C is the crankcase and A 
the admission valve, through which the vapor 














The Automobile Handbook 


299 


passes to the crank case. B is the inlet pas¬ 
sage, through which it passes from the crank 
chamber to the cylinder. P is the piston. The 
igniter, which makes the electric spark when 
the lower point comes in contact with the up¬ 
per, is shown immediately below the cylinder 
cover. This causes the explosion of the vapor. 
E is the exhaust port, through which the burned 
charge escapes after the piston has been driven 
outward by the explosion and has reached the 
end of its stroke. 

Let it be supposed that the motor is still and 
the crank chamber C is full of gas or vapor. 
To start the motor the piston is started by 
means of a crank on the flywheel shaft, and as 
it passes to the position shown in the left-hand 
drawing it forces the charge of vapor through 
the port B into the cylinder. The piston then 
returns to the position shown in the right-hand 
view, moving away from the crank chamber C, 
and in doing so closes the port B and the ex¬ 
haust opening E and compresses the charge of 
vapor. The points of the igniter come together, 
a spark occurs and the resulting explosion 
forces the piston outward again. When the pis¬ 
ton reaches a point near the end of the stroke, 
as shown in the left-hand drawing, it uncovers 
the port E and the burned charge passes out, 
the new charge coming through the port B im¬ 
mediately afterwards. 

The admission of the new charge to the crank 
chamber is controlled by the action of the pis- 


300 


The Automobile Handbook 


ton. As the latter travels outward it has a 
tendency to create a vacuum in the crank 
chamber. This draws the valve inward and 
admits the charge of vapor. 

It will be observed that there is a projection 
on the head of the piston. This is generally 
known as a baffle-plate. Its object is to pre¬ 
vent the incoming charge from passing di¬ 
rectly across the cylinder and out at the ex¬ 
haust port E, which, it will be observed, is di¬ 
rectly opposite it. The baffle-plate directs the 
incoming charge toward the combustion cham¬ 
ber end of the cylinder, providing as nearly as 
may be, a pure charge of vapor and assisting 
in the expulsion of the remainder of the burned 
gases remaining in the cylinder as a result of 
the last explosion. 

Motors —Two and Three Port. In the two- 
port motor, as illustrated in Fig. 133, the func¬ 
tions are as follows: 

The first stroke of the piston produces a vac¬ 
uum in the crankcase and the mixture rushes 
in (as a consequence) through the check valve 
in the motor case. The second stroke com¬ 
presses the mixture, and when the communicat¬ 
ing port is uncovered the mixture surges into 
the cylinder. The next (third) stroke com¬ 
presses the mixture entrapped in the cylinder, 
since the ports are then covered by the piston, 
and at the proper instant the mixture is ignited. 

From this point on it is a normal repetition 
of functions, and once the motor gets under 


The Automobile Handbook 301 

way it two cycles. The three-port motor, Fig. 
134, differs in that the mixture is taken in 
through a third port uncovered by the piston, 
instead of through a check valve in the case! 
and the details in practice change accordingly! 



Two-port Motor Three-port Motor 

Engine, Gasoline, Fuel Consumption of. The 
fuel consumption of a motor is always a serious 
question, and one of importance to the pur¬ 
chaser as well as to the manufacturer. 

Ordinarily about one and two-tenths pints of 
gasoline per horsepower hour under full load 
will cover the fuel consumption. That is, when 

































302 The Automobile Handbook 

the mixture is of the proper explosive quality 
and the water comes from the jacket at a tem¬ 
perature of about 160 degrees Fahrenheit. 

The temperature of the water in the jacket 
around the cylinder has a great deal to do with 
the fuel consumption. 

If the water is forced around the cylinder so 
as to keep it cold, the heat from the combustion 
is cooled down so quickly by radiation that the 
expansive force of the burning gases is mate¬ 
rially reduced, and consequently less power is 
given up by the motor. 

The object of the water is not to keep the cyl¬ 
inder cold, but simply cool enough to prevent 
the lubricating oil from burning. The hotter 
the cylinder with effective lubrication the more 
power the motor will develop. 

Engine, Two-Cycle, Fuel Consumption of. 
The two-cycle engine uses more fuel than the 
four-cycle. The greatest consumption is not so 
■much due to the fact that the two-cycle motor 
makes an explosion for every revolution, in 
contrast with the missed stroke of the four¬ 
cycle, as it is to the fact that there is a consider¬ 
able retention in the cylinder of the exhaust 
charge, and that, despite the deflector, more or 
less of the fresh charge escapes at the exhaust. 
The two-cycle is also harder on a battery owing 
to the greater frequency of the demands upon 
it, but with improved methods of ignition, even 
dry batteries have been found to give very sat¬ 
isfactory service. 



The Automobile Handbook 303 

Engine, Sliding Sleeve Type. The Knight 

sleeve valve engine, Fig. 135, is a four cycle 
gasoline engine in which the usual poppett 
valves have been replaced by two concentric 
sleeves sliding up and down between the 
cylinder walls and the piston. Certain slots in 
these sleeves register with one another at proper 
intervals, producing openings between the com¬ 
bustion chamber and the inlet and exhaust 


Fig. 135 

Knight Sliding Sleeve Engine 
manifolds for the passage of fresh gas into the 
cylinder and burned gas from it. 

It will be noted that the two sleeves are inde¬ 
pendently operated by small connecting rods 










304 


The Automobile Handbook 


working from a shaft made with eccentrics. 
This eccentric shaft is driven at one-half 
crankshaft speed, usually by silent chains. This 
shaft takes the place of, and performs the same 



Inlet Opening on 
Knight Engine 



Inlet Open on 
Knight Engine 


functions as the camshaft in the poppett valve 
engine. The eccentric pins that operate the 
inner sleeves are given a certain advance or 
lead over those operating the outer sleeves., 
This lead, about 90 degrees, together with the 




















































The Automobile Handbook 


305 


half-speed rotation of the shaft, gives the fol¬ 
lowing valve action: 

In Figs. 136 to 142 the relative positions 
of the pistons, sleeves and ports are shown in 



various positions during the two revolutions of 
the crankshaft that make up one working cycle 
of inlet, compression, power and exhaust 
strokes. Fig. 136 shows the inlet just open¬ 
ing. The port, or slot in the inner sleeve is 
coming up, the port in the outer sleeve is go- 






























306 


The Automobile Handbook 


ing down and the passage for the incoming gas 
is forme,d by the rapidly increasing opening be¬ 
tween the upper edge of the slot in the inner 
sleeve and the lower edge of the slot in the 
outer sleeve. 



Fig. 140 Fig. 141 Fig. 142 

Exhaust Opening Exhaust Open Exhaust Closing 


Fig. 137 shows the inlet fully open. The 
inner and outer slots are exactly opposite each 
other and the inlet opening in the cylinder 
wall. Fig. 138 shows the closing of the in¬ 
let. The cylinder has been filled with fresh 
















































The Automobile Handbook 307 

mixture and is ready for the compression stroke. 
Fig. 139 shows the position of the sleeves at 
the top of the compression stroke; the com¬ 
bustion space having been completely sealed by 
the expansion rings in the cylinder head above 
and in the piston below. The firing of the mix¬ 
ture takes place at this point. 

Fig. 140 shows the exhaust port just start¬ 
ing to open. The slot in the outer sleeve is 
coming up and the slot in the inner sleeve is 
going down. Fig. 141 shows the exhaust 
ports fully open. The inner and outer slots 
are opposite each other and at the same time 
opposite the cylinder opening that leads to the 
exhaust piping. Fig. 142 shows the closing 
of the exhaust opening and is practically iden¬ 
tical with the position shown in Fig. 136. 
The four strokes of the cycle (inlet, compres¬ 
sion, power and exhaust) have now been com¬ 
pleted, the crankshaft has made two complete 
revolutions and each sleeve has moved up and 
down once. 

The timing of inlet and exhaust opening and 
closing is not different from that ordinarily used 
in poppett-valve engines, but the opening se¬ 
cured with this construction is greater than 
that ordinarily found in the poppett type. Some 
advantage is also gained because of the more 
direct path, of the incoming and outgoing gases. 
The timing of the valve openings is not affected 
by spring pressure or engine speed. 


308 The Automobile Handbook 

Engines, Eight and Twelve Cylinder Types. 

The development of the automobile engine has 
been along the lines of increase in number of 
cylinders and decrease in the size of the indi¬ 
vidual cylinders, without any considerable in¬ 
crease in the total horsepower delivered by 
the engine. This development has resulted in 
the power being delivered more evenly, inas¬ 
much as an impulse is delivered to the crank¬ 
shaft each time a cylinder fires. With the sin¬ 
gle cylinder engine, one impulse was given for 
each two revolutions and with the increase to 
four, six and eight cylinders, the crankshaft 
has received two, three and four impulses for 
each single revolution. The twelve cylinder 
secures a power stroke for each sixty degrees 
revolution of the crankshaft and consequently 
gives six impulses if or each revolution. 

The most radical change between former 
types of engine and the eight and twelve cylin- 
der types is that of placing the cylinders in 
two equal divisions, and, in place of standing 
vertically, they are placed at an angle of ninety 
degrees in the eight and sixty degrees in the 
twelve. This design does not materially in¬ 
crease the length of the engine over one having 
four or six cylinders of equal size and, of course, 
makes the height somewhat less, due to the in¬ 
clination. While these engines naturally re¬ 
quire additional cylinders, valves, connecting 
rods and pistons, they make use of only one 


The Automobile Handbook 


309 



Fig. 143 

Eight Cylinder Chassis 

















310 


The Automobile Handbook 


crankshaft and generally of but one camshaft. 
No other increase in number of parts or ac¬ 
cessories is necessary, one carburetor, one ig¬ 
nition device and one of each of the other 
power-plant units doing the work for both sets 
of cylinders. 

The mounting and construction of the gener¬ 
ally accepted type of eight cylinder engine is 
shown in Figs. 143 to 145. As will be noted 
from the top view shown in Fig. 143, a space 
is left between the cylinder blocks which pro¬ 
vides suitable location for such fittings as the 
carburetor, the ignition unit and usually the 
lighting dynamo. The valves are located on the 
inside of their respective castings and the re¬ 
sulting position of the caps allows easy re¬ 
moval, inspection and grinding. 

The center lines of the two cylinder blocks 
intersect at the center of the crankshaft, and, 
as will be noted from the side elevation in 
Fig. 144, the crankshaft itself does not dif¬ 
fer from the usual four-throw type used with 
four cylinder ehgines. Depending on the type 
of connecting rod construction used, the cylin¬ 
ders in the blocks are set so that corresponding 
ones on opposite sides are exactly opposite or 
slightly offset from each other in a lengthwise 
direction. In any case the connecting rods 
from the two front cylinders fasten to one 
crankpin, while those from the second cylin¬ 
ders are on the next crankpin, and so on for 
those remaining. 


The Automobile Handbook 


311 



Side View of Eight Cylinder “V” Type Engine 













































































































312 


The Automobile Handbook 


Three types of construction are in use for 
the lower end of the connecting rods; the most 
commonly used method being shown in Figs. 144 
and 145, in which one rod is straight and of 



the usual pattern while the corresponding one 
is forked and has the two sides of the fork so 
placed that they are on either side of the 
straight member. With this construction, the 
crankpin is surrounded with a sleeve or liner 
of bearing metal and the forked rod is clamped 




















The Automobile Handbook 


313 



Fig. 146 

Packard Twelve Cylinder Engine 

















314 


The Automobile Handbook 


around this liner so that the liner is held 
tightly by the rod, and the shaft turns inside 
the liner. The end of the straight connecting 
rod has its bearing on the outside of the liner 
just mentioned and therefore has only a recip¬ 
rocating motion on the liner in place of turn¬ 
ing all the way around. The bearing of the 
straight rod on the liner is adjustable, but the 
liner is not adjustable on the crankshaft. 

Another form of connecting-rod construc¬ 
tion forms one of the rods in the usual way 
with an adjustable bearing on the crankpin. 
On the big end of the rod just mentioned is 
a boss that carries a pin similar to a wristpin, 
and on this pin is mounted the bearing of the 
second connecting rod. The end of the second 
rod does not surround the crankshaft but is 
mounted on the end of the one with the bearing. 

The third form of rod construction is little 
used on eight cylinder types, but is quite com¬ 
mon on twelves. This method uses a complete 
rod end and bearing on each rod, the ends and 
liners being placed side by side so that each con¬ 
necting rod has a bearing on one-half of the 
length of the crankpin. The rods are not in 
the same plane and therefore the cylinders are 
offset, the set on one side of the engine being 
a little forward or back of the opposite set. 
This method allows individual adjustment of 
each bearing. 

In engines with either eight or twelve cylin¬ 
ders, the camshaft is mounted directly above 


The Automobile Handbook 


315 


the crankshaft and therefore between the cylin¬ 
der blocks. Two designs are in common use, 
one making use of separate cams for each of 
the sixteen or twenty-four valves, and the other 
using but one cam for the inlet valves of op¬ 
posite cylinders and another cam for the corre¬ 
sponding exhaust valves. With but one cam 
for two valves, the valve plunger rollers do 
not rest directly on the cam, but the plungers 
are operated from rocker arms, hinged at one 
end to the crankcase and having a roller at the 
end that rests on the cam. When individual 
cams are used for each valve, the cams are of 
necessity placed side by side, but the slight 
distance between each pair makes it necessary 
to offset the valves or offset the cylinder blocks 
in a lengthwise direction. 

As mentioned, it is customary to use one car¬ 
buretor with a manifold that divides near the 
instrument with one branch for each cylinder 
block. Some difficulty was met with in provid¬ 
ing suitable ignition for engines with eight or 
twelve cylinders, but this has been overcome 
by improved forms of ignition breakers, by the 
use of two distributors and two breakers in 
some cases and by the adoption of new prin¬ 
ciples of magneto construction in others. When 
it is realized that a twelve cylinder engine run¬ 
ning at 1,800 revolutions a minute (a moderate 
speed) requires 10,800 accurately timed and 
powerful sparks every minute, the reason for 
the difficulty will be seen. 


316 


The Automobile Handbook 


In considering the firing order of these en¬ 
gines, it should be borne in mind that an eight 
is similar to two four cylinder engines, side by 
side, while a twelve is similar to two sixes. All 
four cylinder engines fire in one of two orders, 
either 1-3-4-2 or else 1-2-4-3, considering the 
front cylinder as number one. Each set of four 
cylinders in an eight, that is, the left hand set 
and the right hand set fires in one of these 
orders, the only difference with the eight being 
that one of the cylinders of the left hand set 
fires just half way between two on the right, 
while each cylinder on the right fires midway 
between two on the left. The cylinders on 
the left, from front to back are usually desig¬ 
nated as No. 1 Left, No. 2 Left, and so on; 
while those in the right are No. 1 Right, No. 
2 Right, etc. The firing order of a number of 
eight cylinder engines is therefore as follows: 
1L, 4R, 3L, 2R, 4L, 1R, 2L, 3R; in which it 
will be seen that, looking at either the “Ls” 
or “Rs,” they fire 1-3-4-2. 

The principles explained above apply equally 
to the twelve, in which the engine may be con¬ 
sidered as two sixes, each set of cylinders fir¬ 
ing in one of the orders possible for a six. It 
is possible to number all the cylinders in either 
an eight or twelve cylinder engine consecutively 
from 1 up and in this case the front right hand 
cylinder is usually called number one. The 
numbering may then continue from front to 
back on the right hand side, in which case 


The Automobile Handbook 


317 


these cylinders will be numbered from 1 to 6, 
or may pass to the left side, calling the left 



Fig. 147 

Section Through Twelve Cylinder Engine 


front cylinder No. 2, the second one on the 
right No. 3, etc. This last method would bring 


































































































318 


The Automobile Handbook 


all the odd numbers on the left and all the even 
numbers on the right. 

Designating the cylinders of a twelve by the 
numbers 1 to 6 and showing their position by 
letters, a common firing order would be as fol¬ 
lows: 1R, 6L, 5R, 2L, 3R, 4L, 6R, 1L, 2R, 5L, 
4R, 3L. This fires each set in the common or¬ 
der: 1-5-3-6-2-4. 

A twelve cylinder engine is shown in Figs. 
146 and 147, and most of the data given in the 
foregoing pages applies equally to the twelve 
and the eight. The principal difference between 
the two types is that the angle included between 
the cylinder blocks of the twelve is less than 
that of the eight, thus leaving less space be¬ 
tween the blocks in the location often called 
the “valve alley .’’ Because of the smaller 
space between the cylinders, a larger one is 
left outside of the cylinders before the sides 
of the hood are reached. This fact has led to 
the practice on twelves of locating the acces¬ 
sories, with the exception of the carburetor, 
outside of the cylinder blocks and in the same 
place that they usually occupy on four and 
six cylinder types. 


The Automobile Handbook 


319 


Exhaust—Cause of Smoky. Smoke coming 
from the exhaust of a gasoline motor is due to 
one of two conditions: Over-lubrication—too 
much lubricating oil being fed to the cylinder of 
the motor- or too rich a mixture, that is, too 
much gasoline and an insufficient supply of air. 

The first condition may be readily detected 
by the smell of burned oil and a yellowish 
smoke. The second, by a dense black smoke 
accompanied by a pungent odor. 

Expansion—Best Conditions for. The effi¬ 
ciency of the expansion in an engine cylinder 
depends upon the initial volume of the charge, 
the condition of the mixture, the compression 
pressure, the point of ignition, the speed of ex¬ 
pansion and the losses due to radiation. 

The losses due to improper expansion may 
therefore be decreased by making large valves 
and valve passages, but these often mean greater 
heat losses. The losses due to radiation may 
be reduced by increasing the temperature of the 
jacket water, and decreasing the area of the 
cylinder. But if the cylinder wall temperature 
is increased, there are considerable difficulties 
with lubrication, and the increased gain in 
thermal efficiency will be more than offset by 
the increased friction. 

In order to obtain the highest efficiency the 
difference in the temperature of the water en¬ 
tering and leaving the cylinder jacket should 
be a maximum. In practical tests it has been 
found that the best results are obtained when 
the jacket water is near the boiling point. 


320 The Automobile Handbook 

Flywheels. One of the first and most impor¬ 
tant considerations in connection with the con¬ 
struction of a gasoline automobile motor is the 
proper diameter and weight of the flywheel. If 
the diameter and weight of the flywheel be 
known, the speed of the motor or its degree of 
compression will become a variable quantity. 
On the other hand, if the speed of the motor 
and the degree of compression be fixed, the di¬ 
ameter or weight of the flywheel rim must be 
varied to suit the other conditions. If the speed 
of the motor and its degree of compression be 
known, the diameter of the flywheel or the 
weight of the flywheel rim may be readily as¬ 
certained from the following formulas. 

Weight of Rims of Flywheels. The weight 
of the rim of the flywheel is the only portion 
which enters into the following calculations, the 
weight of the web, or spokes and hub being 
neglected. 

Let M.P be the mean pressure of the com¬ 
pression, and A the area of the cylinder in 
square inches. If S be the stroke of the piston 
in inches, and N the number of revolutions per 
minute of the motor, let D be the outside diam¬ 
eter of the flywheel in inches and W its re¬ 
quired weight in pounds, then 

M.P X A X S X N 
W =- 


2560 X D 

Diameter of Rims of Flywheels. A motor 



The Automobile Handbook 


321 


that is intended to operate at a slow rate of 
speed, and consequently with a high degree of 
compression, will require a flywheel of much 
greater diameter and weight than a high speed 
motor of the same bore and stroke. It may be 
well to remember that within certain limita¬ 
tions the diameter and weight of a flywheel 
should be as small as is possible, as an increase 
in either means a reduction in motor speed, and 
a consequent loss of power. 

To ascertain the diameter of a flywheel 
when all other conditions are known, if D be 
the required diameter of the flywheel in inches, 
then 

M.P X A X S X N 

D —- 

2560 X W 

Weight of Rims of Flywheels with a Given 
Fluctuation in Speed. If it be desired to run 
a motor at a practically uniform speed and 
with only a slight fluctuation or variation in 
the velocity of the flywheel, if W be the re¬ 
quired weight of the flywheel and x be the al¬ 
lowable fluctuation of the flywheel in revolu¬ 
tions per minute above and below its normal 
speed*, then 

M.P X A X S X N 

W -- 

365 X x 

Horsepower Stored in Rims of Flywheels. 
It is sometimes desirable to know the amount of 





322 


The Automobile Handbook 


energy or horsepower which may be stored in 
the rim of a flywheel of known diameter and 
weight, with a given speed. If H.P be the 
horsepower stored in the rim of the flywheel 
then 

D2 X W X N 

H.P =- 

792,000 

Safe Speed for Rims of Flywheels. The safe 
velocity for the rim of a cast iron wheel is 
taken at 80 feet per second. Let N be safe 
speed of the flywheel in revolutions per minute, 
then 

18,335 
N =- 

D 

The mean pressures corresponding to vary¬ 
ing degrees of compression may be found by 
reference to Table 2. 

M.P = Mean pressure. ’ 

A = Area of cylinder in square inches. 

S = Stroke of piston in inches. 

N = Number of revolutions per minute. 

D == Diameter of flywheel in inches. 

W = Weight of flywheel in pounds. 

Balancing with the Reciprocating Parts of 
the Motor. The flywheel should be balanced 
as accurately as is possible before mounting 
on the crank shaft. In the first place set the 
crank shaft on two perfectly straight parallel 
bars, one bar under each end. Then attach the 




The Automobile Handbook 


323 


connecting rod and piston to the crank and 
turn the shaft until the crank jaws are parallel 
with the floor, or in other words, at right angles 
to a perpendicular line drawn through the cen¬ 
ter of the shaft. Place a scale under the crank 
pin, or use a hanging scale attached to some 
rigid support above the pin and connect it to 
the crank pin by a wire or cord sufficiently 
strong to carry the weight. Then find the 
weight of the parts according to the scale and 
attach the same amount to the flywheel at the 
same distance from the shaft on the side oppo¬ 
site the crank, and the result will be a fairly 
balanced motor. It is impossible to obtain a 
perfect balance, but the above method will 
assist greatly in reducing the vibration of the 
motor. 

While it is true that the weight of the flywheel 
may be reduced as the number of cylinders is 
increased, there is a practical limit below which 
it is inadvisable to reduce the weight at the 
rim. Even should the number of cylinders be 
sufficient to cause a balance between the work¬ 
ing strokes, it would still be desirable to add a 
rotating weight to compensate in some measure 
for the several reciprocating masses, such as 
pistons, connecting rods, crankshaft webs, etc. 
Engines have been built for racing purposes 
without flywheels, but they were unsuccessful. 

Friction. Friction, being the resistance to 
motion of two bodies in contact, depends upon 


324 


The Automobile Handbook 


the following laws: It will vary in proportion 
to the pressure on the surfaces; friction of 
rest is greater than friction of motion; the to¬ 
tal friction is independent of the area of the 
contact surfaces when the pressure and speed 
remain constant; and friction is greater be¬ 
tween soft bodies than hard ones. 

The behavior of lubricated surfaces is quite 
different from dry ones, the laws of fluid fric¬ 
tion being independent of the pressure between 
the surfaces in contact, but it is proportional to 
the density of the fluid and in some manner to 
the viscosity. When a bearing is thoroughly 
lubricated it does not seem to make much dif¬ 
ference what the metals are, because there is a 
layer of oil running around with the journal 
and sliding over another layer adhering to the 
bearing. If, however, the feed fails, or the pres¬ 
sure gets too heavy for the nature of the lubri¬ 
cant, and so squeezes it out, or the temperature 
has risen so high as to affect the body of th$ 
oil, then the surfaces come into contact and the 
peculiar nature of the contact asserts itself, 
some combinations abrading and seizing more 
readily than others. When the lubrication is 
thorough, the condition of the fluid friction be¬ 
ing realized, the intensity of the load makes less 
difference than would be expected. 

Fuels for Automobiles. Apart from the pos¬ 
sibility of an increase in the fuel resources of 
the world due to some revolutionary discovery, 
the ingredients in any mixed fuel for automo- 


The Automobile Handbook 


325 


bile use must be confined to the following list, 
in which, for completeness, gasoline is in¬ 
cluded : 

Gasoline. Average composition, C=84, H= 
16. 

Source, petroleum. 

Boiling point, 50° to 150° Cent. 

Specific gravity, .680 to .720. 

Calorific value, 19,000 B. T. U. 

Latent heat, small. 

Benzine. Average composition, C=92, H 
= 8 . 

Source, coal tar. 

Boiling point, 80° Cent. 

Freezing point, 5° Cent. 

Specific gravity, .899. 

Calorific value, 19,000 B. T. U. 

Latent heat, small. 

Alcohol. Average composition, C=32, H=8, 
0=35. 

Source, vegetable matter, principally corn, 
beets, potatoes, sugar cane. 

Boiling point, 70° Cent. 

Specific gravity, .806. 

Calorific value, 12,600 B. T. U. 

Latent heat, considerable. 

Tar Benzol. Average composition, C=92, 
H=:8. 

Source, a by-product in the manufacture of 
coke. 

Boiling point, 80° to 120° Cent. 

Specific gravity, .895. 


326 


The Automobile Handbook 


Calorific value, 19,000 B. T. U. 

Latent heat, small. 

Kerosene. Average composition, C=85, 
H=15. 

Source, petroleum. 

Boiling point, 150° to 300° Cent. 

Specific gravity, .800 to .825. 

Calorific value, 19,000 B. T. U. 

Latent heat, considerable. 

Motor Spirit, Naphtha, Benzoline, Benzine. 
Average compositnon, C=85, H=15. 

Source, petroleum and shale. 

Boiling point, 60° to 160° Cent. 

Specific gravity, .750. 

Calorific value, 19,000 B. T. U. 

Latent heat, appreciable. 

Methyl Alcohol, Wood Spirit, Naphtha. Av¬ 
erage composition, C=38, H=12, 0=50. 
Source, the distillation of wood. 

Boiling point, 66° Cent. 

Specific gravity, .812. 

Calorific value, 9,600 B. T. U. 

Latent heat, appreciable. 

Acetylene Ethene. Average composition, 
C=92, H=8. 

Calorific value, 25,000 B. T. U. 


The Automobile Handbook 327 

Fuel Feed, Vacuum. 

The Stewart vacuum gasoline tank, Figs. 148 
to 152, consists of two chambers. The upper 
one is the float or filling chamber, and the lower 
one is the reservoir or empty chamber. The 
upper chamber is connected with the intake 
manifold of the motor, and also with the main 
gasoline supply tank. The lower or emptying 
chamber is connected with the carburetor. Be¬ 
tween these two chambers is a valve. The 
suction of the piston on the intake stroke creates 
a vacuum in the upper chamber. This closes 
the valve between the two chambers, and in 
turn draws gasoline from the main supply tank. 
The gasoline, being sucked or pumped up into 
this upper chamber, operates a float valve. 
When this valve has risen to a certain mark 
it automatically shuts off the suction valve-and 
opens an air valve. This open air valve creates 
an atmospheric condition in the upper chamber 
and opens the valve into the lower chamber, and 
the gasoline immediately commences to flow to 
the lower or emptying chamber. The lower 
chamber is always open to outside atmospheric 
conditions, so that the filling of the upper cham¬ 
ber in no way interferes with an even, uninter¬ 
rupted flow of gasoline from this lower cham¬ 
ber to the carburetor. 

A is the suction valve for opening and clos¬ 
ing the connection to the manifold and through 
which a vacuum is extended from the engine 
manifold to the gasoline tank. 


328 


The Automobile Handbook 


AIR VENT- 


D- 


TO INTAKE j 
MANIFOLD 



. v to CARBU^I 
-|-V f RETOR 

Fig. 148 

Stewart Vacuum Fuel Feed Tank 




































The Automobile Handbook 329 

B is the atmospheric valve, and permits or 
prevents an atmospheric condition in the up¬ 
per chamber. See Fig. 149. When the sue- 



Float and Levers of Vacuum Tank 
tion valve A is open and the suction is drawing 
gasoline from the main reservoir, this atmos¬ 
pheric. valve B is closed. When the suction 



























330 The Automobile Handbook 


Fig. 

Arrangement of Parts 


150 

of Vacuum Fuel Feed 













The Automobile Handbook 331 

valve A is closed, then the atmospheric valve 
B must be open, as an atmospheric condition is 
necessary in the upper tank in order to allow 
the fuel to flow through the flapper valve H 
into the lower chamber. 

C is a pipe connecting tank to manifold of 
engine. 

D is a pipe connecting vacuum tank to the 
main gasoline supply tank. 

E is a lever to which the two coil springs S 
are attached. This lever is operated by the 
movement of the float G. 

F is a short lever, which is operated by the 
lever E and which in turn operates the valves 
A and B. 

G is the float. 

H is flapper valve in the outlet T. This 
flapper valve is held closed by the action of 
the suction whenever the valve A is open, but 
it opens when the float valve has closed the 
vacuum valve A and opened the atmospheric 
valve B. 

J is a pet cock for drawing water or sedi¬ 
ment out of the reservoir. This may also be 
used for drawing gasoline for priming or clean¬ 
ing purposes. 

K is a line to the carburetor extended on in¬ 
side of the tank to form a pocket for trapping 
water and sediment which may be drawn out 
through pet cock J. 

L is a channel space between inner and outer 
shells, and connects with air vent R, ihus main- 


332 The Automobile Handbook 

taining an atmospheric condition in the lower 
chamber at all times, and thereby permitting 
an uninterrupted flow of gasoline to the carbu¬ 
retor. 

M is the guide for float. 

R is an air vent over the atmospheric valve. 
See Fig. 151. The effect of this is the same 
as if the whole tank were elevated and is for 
the purpose of preventing an overflow of gaso¬ 
line should the position of the car ever be such 



Fig. 151 


Upper Connections of Vacuum Tank 
as would raise the gasoline supply tank higher 
than the vacuum tank. Through this tube also 
the lower, or reservoir chamber, is continually 
open to atmospheric pressure, so that the flow 
of gasoline from this lower chamber to the car¬ 
buretor is always allowed. 

T is the outlet located at the bottom of the 
float reservoir in which is the flapper valve H. 

The flapper valve is ground on its seat and 
should be trouble-proof. A small particle of 
dirt getting under the flapper valve might pre- 






The Automobile Handbook 333 

vent it from seating absolutely air-tight and 
thereby render the tank inoperative: In order 
to determine whether or not the flapper valve 
is out of commission, first plug up air vent; 
then detach tubing from bottom of tank to 
carburetor. Start motor and apply finger to 
this opening. If suction is felt continuously, 
then it is evident that there is a leak in the 
connection between the tank and the main gas¬ 
oline supply or else the flapper valve is being 
held off its seat and is letting air into the tank 
instead of drawing gasoline. 

Any troublesome condition of the flapper 
valve can be remedied by removing tank cover, 
then lift out the inner tank. Fig. 152. The 
flapper valve will be found screwed into the 
bottom of this inner tank. 

Coupling and elbow connections should be 
kept screwed down tight. Care should be taken 
that tubing contains no sharp flat bends that 
might retard the gasoline flow. 

Gasoline for priming or. cleaning purposes 
can be obtained by opening pet cock. 

To make certain that the tank is not at fault 
in case of trouble, take out the inner tank en¬ 
tirely. This will leave only the outer shell, 
which will then be nothing more than an or¬ 
dinary gravity tank. Fill this tank with gas¬ 
oline and start to run. If you still have trouble 
it will be apparent that the fault lies elsewhere 
and not in the tank. 


334 The Automobile Handbook 

Carburetor pops and spits are due to im¬ 
proper carburetor adjustments. Running the 
engine at low speed with an open throttle for 
any length of time might not produce sufficient 
suction to fill the tank when empty. But this 
condition might take place because of dirt or 
foreign matter getting in and clogging the gas¬ 
oline feed tube. 

If you have any doubt as to the tank being 
full of. gasoline, it is only necessary to close the 
throttle and the suction of the motor will then 
fill the tank almost instantly. 

To fill the tank, should it ever become en¬ 
tirely empty, close the engine throttle and turn 
the engine over a few revolutions. This will 
create sufficient vacuum in the tank to fill it. 
If the tank has been allowed to stand empty 
for a considerable time and does not easily fill 
when the engine is turned over, look for dirt or 
sediment under the flapper valve H, or the 
valve may be dry. Removing the plug W in 
the top and squirting a little gasoline into the 
tank will wash the dirt from this valve; also 
wet the valve and cause the tank to work im¬ 
mediately. This flapper valve sometimes gets 
a black carbon pitting on it, which may tend 
to hold it from being sucked tight on its seat. 
In this case the valve should be scraped with a 
knife. 

If the motor speeds up when the vacuum tank 
is drawing gasoline from the main supply it 
shows that either the carburetor mixture is too 


The Automobile handbook 


335 


rich, or the connections are so loose that it ig 
drawing air into the manifold. There should 



TO CARBURETOR 


Fig. 152 

Shell of Vacuum Tank 


be no perceptible change of engine speed when 
the tank is operating. 












































236 


The Automobile Handbook 


Gases, Expansion of. All gases expand 
equally, 1/273 part of their volume for each 
degree of temperature, Centigrade, of 1/491 
part of their volume for each degree of temper¬ 
ature, Fahrenheit. 


Gasoline, How Obtained. Benzine, Gasoline, 
Kerosene and the kindred hydro-carbons are 
products of crude petroleum. 

They are separated from the crude oil by a 
process of distillation. The process is very sim¬ 
ilar to that of generating steam from water. 

Crude petroleum subjected to heat will give 
off in the form of vapor such products as Ben¬ 
zine, Gasoline and Kerosene, etc. The degrees 
of heat at which these products are separated 
are comparatively low. Various degrees of heat 
will separate the distinct products. As a means 
of illustration, it may he said that the crude oil 
when raised to certain temperatures gives off 
vapors which when cooled liquefy into oils. 

Viscosity of Gasoline. It is a mistake to 
assume that because gasoline does not thicken 
up, it is retarded in its flow through the nozzle 
of the carbureter. Taking gasoline having a 
specific gravity of 0.71 the quantity that will 
pass through the nozzle of a carbureter under a 
given pressure will increase as the temperature 
is increased, as shown in the following table: 


Temp, degrees P. 

50 ® . 

59 ° . 

68 ° . 

77 * . 

86 ® . 

95 ° . 


Relative Flow. 

.1 

. 1.073 

. 1.145 

. 1.212 

. 1.27 

. 1.335 








The Automobile Handbook 


337 


Since carbureter nozzles are not readily ad¬ 
justable, nor with any degree of certainty, it 
follows from the above that the influence of tem¬ 
perature upon the weight of fuel ejected will 
most certainly affect the efficiency of the car¬ 
bureter. This source of trouble goes to indi¬ 
cate that some means of maintaining a constant 
temperature is of the greatest advantage, and 
in a measure it argues for the adaptation of 
water (hot) jacketing, not around the depres¬ 
sion chamber, as is usually the practice, but 
around the gasoline (float) bowl, in order to 
maintain a constant temperature of the liquid 
gasoline as it flows through the nozzle. 

Gasoline Explosions. There are two entirely 
different kinds of explosion, which would un¬ 
doubtedly both be referred to as gasoline ex¬ 
plosions. The real gasoline explosion is the 
kind taking place in the cylinder of a gasoline 
motor, in which heat and pressure are suddenly 
produced by the combustion of gasoline vapor 
in air. The other kind of explosion referred to 
may be explained as follows: 

If a tank of gasoline be placed on a woodpile 
and the latter set on fire, the heat would 
raise a pressure in the tank, which would rap¬ 
idly increase and the tank would finally explode 
from the pressure. The gasoline would then 
be thrown in all directions, and, owing to its 
superheated condition, the greater part of it 
at least would instantly vaporize, mix with the 


338 The Automobile Handbook 

air of the atmosphere and be ignited by the 
flame which caused the explosion. 

Gasoline Fires, Extinguishing. A number of 
fires have been caused by leaky gasoline pipes 
on automobiles, and many persons would like to 
know of chemicals which can be used to put 
out such fires. Water is exceedingly danger¬ 
ous to use, and it is not always possible to get 
at the fire to smother it with wet rags or waste. 

In case of fire due to gasoline, use fine earth, 
flour or sand on top of the burning liquid. 

A dry powder can be used for this purpose 
which will extinguish the fire in a few seconds. 
It is made as follows: Common salt, 15 parts— 
sal-ammoniac, 15 parts—bicarbonate of soda, 
20 parts. The ingredients should be thoroughly 
mixed together and passed through a fine mesh 
sieve to secure a homogeneous mixture. 

If by any chance a tank of gasoline takes fire 
at a small outlet or leak, run to the tank and 
not away from it, and either blow or pat the 
flame out. Never put water on burning gaso¬ 
line or oil, the gasoline or oil will float on top 
of the water and the flames spread much more 
rapidly. 

Several gallons of ammonia, thrown in the 
room with such force as to break the bottles 
which contain it, will soon smother the strong¬ 
est fire if the room be kept closed. 

It is not advisable to operate a pleasure car, 
and certainly not a truck, without having a port¬ 
able extinguisher on the car. Such extinguish- 


The Automobile Ha/udbooh 339 

ers are made in sizes suitable for carrying in an 
easily accessible place and should be so mounted. 
A fire starting in the under-pan or under the 
hood may be smothered in the beginning, while 
delay would mean the car’s destruction. 

Gasoline, Thermo-dynamic Properties of 
Gasoline and Air. The following table, 8, 
gives the thermo-dynamic properties of gaso¬ 
line and air, and may be of interest, in view of 
the fact that information on this subject is 
sparse, and most of that only theoretical, or 
empirical deductions. 

This table gives the explosive force in pounds 
* per square inch of mixtures of gasoline vapor 
and air, varying from 1 to 13 down to 1 to 4, 
also the lapse of time between the point of igni¬ 
tion and the highest pressure in pounds per 
square inch attained by the expanding charge 
of mixture. The tests from which the results 
given were obtained, were made with a charge 
of mixture at atmospheric pressure, so as to 
more accurately note the results, as the mixture 
takes much longer after ignition to attain its 
highest pressure, and is slower also in expand¬ 
ing. 

It may be well to remember that there are no 
more heat-units, and consequently no more foot¬ 
pounds of work in a mixture of gasoline and air, 
under 5 atmospheres compression, than under 
1 atmosphere compression. 

Flanged or ribbed air-cooled motor* will ap¬ 
proach the figures given in the table for the 


340 The Automobile Handbook 

initial explosive force for the varying compres¬ 
sions, very closely, while thermal-siphon wa¬ 
ter-cooled motors will come within about 20 
per cent of these results, and pump and radiat¬ 
ing coil cooled motors will come within about 
30 per cent. While it appears at the first glance 
that the proper thing to do to get the greatest 
efficiency from a motor would be to let it run 
as hot as possible, experience has shown that 
the repair bill of a hot motor will more than 
offset its efficiency over the cooler water-jack¬ 
eted motor, with pump and radiating coils. The 
last two columns in the table give the tempera¬ 
ture of the burning gases, the first of the two 
columns the actual temperature with the ac¬ 
companying mixture of gasoline and air, and 
the second the theoretical temperatures, or tem¬ 
perature to which the burning mixture should 
attain, if there were no heat losses. 


TABLE 8. 

THERMO-DYNAMIC PROPERTIES OP GASOLINE AND AIR. 


Gasoline, 
Vapor and 
Air. 


Time in 
Seconds 
between 
Ignition 
and 

Highest 

Pres¬ 

sure.* 


Explosive Force in 
Pounds per sq. in. 

Compression 
in Atmospheres. 


Temperature 
of Combustion 
in Degrees 
Fahrenheit.* 

3 

4 

5 

Actual. 

Theo¬ 

retical. 

1 to 13 


0.28 


156 

208 1 

260 


1857 

3542 

1 to 11 


0.18 


183 

244 

305 


2196 

4010 

1 to 9 


0.13 


234 

312 

390 


2803 

4806 

1 to 7 


0.07 


261 

348 

435 


3119 

6001 

1 to 5 


0.05 


270 

360 

450 


3226 

6854 

1 to 4 


0.07 


240 

320 

400 


2965 

5517 


*At atmospheric pressure. 



















The Automobile Handbook 341 

Gearless Transmission. This name has been 
applied to a wide variety of transmission, or 
change speed devices. It is quite customary to 
refer to the friction drive as a gearless system, 
and this is true to the extent of not using 
toothed gearing of any form. 

A car using this name was built several years 
ago, and its construction embodied a novel 
method of change speed mechanism. The trans¬ 
mission system of the gearless car made use of a 
central cone, long in proportion to its diameter, 
and faced with friction material. Placed so that 
they might engage with this driving member, 
were several sets of rollers, which were, in turn, 
brought into contact with driven members or 
clutches. The principle of operation was that 
of the planetary, or internal epicyclic, gear. In 
place of using toothed gears, this car secured its 
drive by bringing one or the other sets of rollers 
into play and thereby secured three forward 
speeds and one reverse. Large power was trans¬ 
mitted and little trouble found. 

Gears, Diametrical Pitch System of. Table 
9 gives the necessary dimensions for lay¬ 
ing out and cutting involute tooth spur gears 
from No. 16 to No. 1 diametral pitch. Formulas 
are also given so that if the number of teeth 
and the diametral pitch are known, the pitch 
diameter can be ascertained—also, the diam¬ 
etral pitch, outside diameter, number of teeth, 
working depth, and clearance at bottom of 
tooth: 


342 


The Automobile Handbook 


P = Pitch diameter in inches. 

D = Diametral pitch. 

W = Working depth of tooth in inches. 

T = Thickness of tooth in inches. 

0 = Outside diameter in inches. 

C = Circular pitch in inches. 

T 

(1) Pitch diameter=— 

D 

2 

(2) Outside diameter=P-|— 

D 

T 

(3) Diametral pitch;=— 

P 

3.142 

(4) Circular pitch=- 

D 

2 

(5) Working depth of tooth=—=2-^D 

D 

(6) Number of teeth=PXD 

(7) Thickness of tooth=1.57lXD 

C 

(8) Clearance at bottom of tooth=— 

20 

For example: Required, the pitch diameter 
of a gear with 20 teeth and No. 5 diametral 



The Automobile Handbook 


343 


pitch. From Formula No. 1, as the pitch diam¬ 
eter is equal to the number of teeth divided by 
the diametral pitch, then 20 divided by 5 
equals 4, as the required pitch diameter in 
inches. 

What is the outside diameter of the same 
gear? From Formla No. 2, as the pitch diam¬ 
eter is 4 inches, and the diametral pitch No. 
5, then 4 plus 2/5 equals 4 2/5 as the proper 
outside diameter for the gear. 

What would be the diametral pitch of a 
gear with 30 teeth and 5 inches pitch diame¬ 
ter? From Formula No. 3, 30 divided by 5 
equals 6, as the diametral pitch to be used for 
the gear. In this manner by the use of the 
proper formula any desired dimension may be 
obtained. 


TABLE 9. 

DIMENSIONS OF INVOLUTE TOOTH SPUR GEARS. 


Diametral 

Pitch. 

Circular 

Pitch. 

Width of 
Tooth on 
Pitch 
Line. 

Working 
Depth of 
Tooth. 

Actual 
Depth of 
Tooth, 

Clearance 
at Bottom 
of Tooth 

1 

3.142 

1.571 

2.000 

2.157 

0.157 

2 

1.571 

0.785 

1.000 

1.078 

0.078 

3 

1.047 

0.524 

0.667 

0.719 

0.052 

4 

0.785 

0.393 

0.500 

0.539 

0.039 

5 

0.628 

0.314 

0.400 

0.431 

0.031 

6 

0.524 

0.262 

0.333 

0.360 

0.026 

7 

0.447 

0.224 

0.286 

0.308 

0.022 

8 

0.393 

0.196 

0.250 

0.270 

0.019 

10 

0.314 

0.157 

0.200 

0.216 

0.016 

12 

0.262 

0.131 

0.167 

0.180 

0.013 

14 

0.224 | 

0.112 

0.143 

0.154 

0.011 

16 

0.196 | 

&.098 

0.125 

0.135 

0.009 


Gears, Horsepower Transmitted by. The fol¬ 
lowing formulas will give the horsepower that 












344 


The Automobile Handbook 


may be transmtited by gears with cut teeth of 
involute form and of various metals. 

H.P = Horsepower. 

P = Pitch diameter in inches. 

C = Circular pitch in inches * 

F = Width of face in inches. 

R = Revolutions per minute. 

PXCXFXP 

H.P=-(Annealed tool steel.) (1) 


(Mach, steel or Phos¬ 
phor Bronze.) (2) 

(Cast Brass.) (3) 


(Cast Iron.) (4) 

Example: Required, the horsepower which 
a tool steel pinion, 2 inches pitch diameter, 1 
inch face and No. 10 diametral pitch, will 
transmit at 900 revolutions per minute. 

Answer: From the table the circular pitch 
corresponding to No. 10 diametral pitch is 

♦The circular pitch corresponding to any diametral pitch num¬ 
ber, may he found by dividing the constant 3.1416 by the diam- 

etr Example: What is the circular pitch in inches corresponding 
to No. 6 diametral pitch. . ^ . , 

Answer: The result of dividing 3.1416 by 6 gives 0.524 inches 
as the required circular pitch. 


H.P=- 


90 

PXCXFXR 

140 

PXCXFXR 


H.P=- 


410 

PXCXFXR 


H.P=- 


550 







The Automobile Handbook 


345 


0.314. Then by Formula No. 1, 2X0.314X1X 
900 equals 565.2. This, divided by 90, gives 
5.29 horsepower. 

Gear, Internal-Epicyclic. It is often desired 
to ascertain the speed of rotation of the differ¬ 
ent members of this form of gearing. To cal¬ 
culate their speeds, the following formulas are 
given, which, by reference to the letters desig¬ 



nating the different parts in Figure 153, may be 
readily solved. 

Let R be the revolutions per minute of the 
disk or spider carrying the pinions D. 

Let N be revolutions per minute of the gear 
E. 

Let G be the revolutions per minute of the 
internal gear F. 

When the internal gear F is locked and gear 
E rotating, the speed in revolutions per minute 
of the disk or spider carrying the pinions D is 



346 


The Automobile Handbook 


E 

R = N - 

E + F 

If the internal gear be locked and the spider 
carrying the pinions D be rotated, then the 
speed in revolutions per minute for the gear E 
will be 

E + F 

N = R - 

E 

If the spider carrying the pinions D be held 
rigid and the gear E be rotated, the speed in 
revolutions per minute for the internal gear F is 

NXE 

G =- 

F 

If the pitch diameter of the gears is not read¬ 
ily obtainable, the number of teeth in each gear 
may be used instead, as the result will be ex¬ 
actly the same. 

It will be recognized that this is the form of 
gearing employed in the older forms of plane¬ 
tary transmission devices. Newer types use no 
internal toothed gears. 

Heat of Combustion. The quantity of heat 
generated by the complete combustion of vari¬ 
ous gases and petroleum products is known 
as the heat value of the fuel, and represents the 
maximum amount of heat that can be obtained 
from a given quantity of the fuel. No accurate 





The Automobile Handbook 347 

rule has yet been devised by which to compute 
the heat value of any chemical compound from 
its formula and the heat values of the elements 
of which it is composed. Hence, the heat values 
of compounds must be found by a separate de¬ 
termination for each one in the laboratory. The 
heat developed by the combustion of some of 
the commoner fuels and gases is given in Table 
14. In the case of carbon, the heat developed 
by its complete combustion, forming C0 2 , and 
the heat of its partial combustion to CO, are 
given; also the heat of combustion of CO to 
C0 2 . 

Heat Value of a Mixture. The heat value 
of a mixture may be found from the heat val¬ 
ues of the substances of which it is composed 
and the percentage of each substance. If h A , 
h 2 , h 3 , etc., represent the heat values of the 
substances forming the mixture, and p A , p 2 , p 3 , 
etc. represent the percentage of each substance, 
the heat value of the mixture will be repre¬ 
sented by the following formula: 

hm=p 1 h 1 +p 2 h 2 +p 3 h 3 +etc. 

Example.—A certain gas has the following 
composition: 


Constituents of Gas Per Cent. 

Hydrogen, H . 20 

Marsh gas, CH 4 . 70 

Acetylene, C 2 H 2 . 10 


What is the heat value per cubic foot of the 
mixture ? 

Solution.—Referring to Table 10, the heat 





TABLE 10. 

MIXTURES OF AIR AND GASES, AND RESUITING HEAT OP COMBUSTION 


348 


✓ 

The Automobile Handbook 


Heat of 
Combustion 

B. T. U. 

per 

Cubic 

Foot of 

Gas at 

62° 

. . • . -Tt* 

• • <M • • M -HGOOWO 

• * CO * * CO ' O iO N GO Tf 

• • • • • 

• • •• •rHrtfHCO’H 

B. T. U. 

per 

Pound 

of Fuel 

. *000*0 • cO CO O CO h 

. ‘OOOOO -NNkOCOiN 

• -O^COCO • o ^ CO *-H ^ 

• • C^f ^ ^ • CO 1-H <M~ 00 T-T 

• • O f-1 *NNWrt(N 

Specific 
Heat of 
Gas at 
Constant 

Pressure 

.21751 

.24380 

3.40900 

.24790 

.21700 

.59290 

.40400 

.37540 

Weight 
Required to 
Burn 1 
Pound of 

Gas 

Pounds 

Air 

• • • • GO • CD ^D • • • 

• -OO • • ^ • Tt« O • • • 

• • • • • 

• • CO • • • ▼■H *-H • • • 

O 

• • O • • • O CO • • • 

• • O • • to • O Tf< • • • 

• • 00 • • • CO • • • 

Volume 
Required 
to Burn 1 
Cubic Foot 
of Gas 

Cubic Feet 

Air 

• *00 • • OO •WOOCONOi 

• -CO • -CO • iO <M O • • 

• . • • • • »C H 

• • 03 • • • C5 CO CO 

• • • *-H 

O 

• *0 • • *0 -00*0*0*0 

• • • • e* co co o* 

Volume of 

1 Pound of Gas 
at Atmospheric 
Pressure 

Cubic Feet 

o 

o 

oo *oo • • *o OCO*ON^CO 

00 *0 00 • • *0 (ONtOONO 

COO • -CO OO CO CO 03 Tt< 

HOO • -H C4 »H fH 

T—4 • 

o 

CO 

o o • • 

0* OO • • iHCONOi^N 

03 00 • *<M OOMNih^cO 

• 

Weight 
of Gas 
at 30°, 
per 
Cubic 
Foot 

Pound 

!>• 03 • CO 00 O O CO H 

^ CO * • O (N CO CO CO CO lO 

O 00*0 • *ts* CO *0 00 CO CO <M 

OO O • • (N^NOOMN 

O OO • *0 *-<000030 

V 

Chemical Proportions 

.t! -z * 

co o • *< 

. > • w wQ 

£o I <© «OOo^ 

|§ : 3 

2 » : i i+++? 

11 2 : o ooo^i 

-Q > -O ” M 

iWogBo u ii h q h 
++;■?■■£ ooogo 
'o -o " 0 o r 'f 4 __, 1 , 

°.-£ : lOc^iO «+++++ 

£ >.b ' i i ^£0 ® “ « 

co- 

C<I CS) nOOOh OOOOO 

Fuel 

Oxygen, 0. 

Nitrogen, N. 

Hydrogen, H. 

Carbon, C. 

Carbon, C. 

Carbon monoxide, CO. 
Carbon dioxide, CO 2 .. 

Methane, CH«. 

Ethylene, C 2 H 4 . 

Ethane, C 2 H 6 . 

Benzol vapors, CeH6.. 
Acetylene, C 2 H 2 . 

































































The Automobile Handbook 349 

values per cubic foot of these gases are seen to 
be 327, 1,010 and 1,464 B. T. U., respectively. 
Apply the formula just given. p x = .20, p 2 = 
.70, and p 3 = .10. Also, h ± = 327, h 2 = 1,010, 
and h 3 = 1,464. Substituting, hm = .20 X 327 
+ .70 X 1,010 + .10 X 1,464 = 65.4 + 707 + 
146.4 = 918.8 B. T. U. Ans. 

Temperature of Combustion. The theoret¬ 
ical temperature of the combustion of a given 
filel can easily be calculated. Making no al¬ 
lowance for losses of heat, and supposing that 
just enough air is furnished for the combustion, 
burning carbon should have a temperature 
about 4,940° above zero; while burning hydro¬ 
gen should have a temperature about 5,800° 
above zero. In practice, these temperatures 
are never attained, on account of heat losses. 

Loss of Heat. The loss of heat from any hot 
object is accomplished in three ways: by con¬ 
vection, by conduction and by radiation. In 
all practical cases a body loses heat by a com¬ 
bination of these processes. 

When heat is produced in the cylinder by the 
combustion of the gases, the piston is at or near 
the upper dead center; that is, it remains nearly 
stationary when the heat is greatest and when 
the heat loss per unit area of inclosing walls is 
most rapid. 

Under the usual conditions of ignition, the 
gas contained in the cylinder must be set into 
violent motion by the spread of the flame 
through it, and this motion will aid the dissipa- 


350 


The Automobile Handbook 


iion of the heat in the gas to the containing 
walls. So convection will be an important fac¬ 
tor in the process and perhaps the principal 
factor. Perhaps a part of the gain in power 
which has resulted, in some instances, from the 
use of multiple ignition may be due to violent 
motion of the gas. Practically all air cooled 
motors have their valves in the head, so the 
charge is contained between the cylinder walls 
and the piston head. 

The heat absorbed by the water-jacket is 
equal to the weight of water passed through the 
jacket multiplied by the temperature range; or, 
in other words, it is the difference between the 
temperature of the water when it enters the 
water-jacket and that of the water when it 
leaves the jacket. For instance, if the tempera¬ 
ture of the entering water is 50° and that of 
escaping water is 180°, the temperature range 
is 180°—50° = 130°. Then, if the weight of 
the water passing through the jacket in 1 hour 
is 100 pounds, the heat carried away is 100 X 
130 = 13.000 British thermal units. 

Horsepower. The actual horsepower of an 
engine can only be determined by making a 
test with suitable brakes or dynamometers. 
This method would give the actual brake horse¬ 
power. In order to allow ready calculation, the 
Society of Automobile Engineers * formula is 
used and is generally recognized. The bore or 
diameter of the cylinder is first squared; that 
is, the size in inches is multiplied by itself. This 


The Automobile Handbook 351 

number is then multiplied by the number of 
cylinders and the result divided by 2y 2 . Thus, 
for an engine with 5-inch bore: 5x5=25. If 
of 4 cylinders, 25x4=100, and 100 divided by 
2]/ 2 gives the result as 40 horsepower. In order 
to secure approximately correct results, the en¬ 
gine is supposed to be operating at 1,000 feet 
per minute piston speed. 

Horsepower of Explosive Motors. The first 
requisite is to find the number of power strokes 
made per minute by the motor. In a single 
cylinder motor of the four-cycle type there is 
one power stroke for every two revolutions, 
and if the motor has four cylinders there is 
one power stroke for every revolution of the 
crank shaft. The number of power strokes then 
may be found by the following formula (refer¬ 
ring to a four-cycle motor) : 

C 

N = -XS 
4 

in which N = Number of power strokes per 
minute. 

C = Number of cylinders. 

S = Angular velocity of crank shaft in rev¬ 
olutions per minute. 

Having ascertained the number of power 
strokes per minute, the horsepower is found by 
the formula, 

PLAN 
H.P -- 


33,000 



352 


The Automobile Handbook 


P = Mean effective pressure (M. E. P.). 

L = Length of stroke in feet. 

A = Area of piston in sq. in. 

N = Number of power strokes per minute. 
This formula does not discriminate between 
mechanical friction and losses in “fluid” fric¬ 
tion. A formula that is more arbitrary and 
that fits the majority of cases, requiring only 
the use of a few facts, such as diameter of cyl¬ 
inder, length of stroke, and revolutions per min¬ 
ute, is presented as follows: 

VXN 

H.P =- 

10,000 

in which 

V = volume of cylinder in cu. inches. 

N = number of power strokes per min. 

The constant used varies from 9,000 to 14,000 
depending upon certain types of engines; 10,000 
being an average figure for four cycle engines. 
The brake horsepower will be from 65 to 85 per 
cent of the result obtained; 80 per cent may be 
taken as an average. As an example we may 
take a four-cycle, four-cylinder motor 4%-in. 
bore and 4y 2 -in. stroke making 1,200 power 
strokes per minute. Volume (V) of cylinder 
equals area of piston 15.9 sq. in. X length of 
stroke 4 1 /2=71.55 cu. in., and multiplying this 
by 1,200 (N) and dividing the product by 10,- 
000 gives 8.05 H.P. Taking 80 per cent of this 
as the brake horsepower the result is 6.44 H.P. 



The Automobile Handbook 


353 


From a theoretical standpoint a two-cycle ex¬ 
plosive motor should not only have as great a 
speed, but also be capable of developing almost 
twice the power that a four-cycle motor does. 
It is a fact nevertheless that its actual perform¬ 
ance is far different. 

The horsepower of a two-cycle motor may be 
calculated from the following formula, 

d 2 xsxn 

H.P=- 

21,000 

in which 

D=diameter of cylinder in inches. 

S=stroke of piston in inches. 

N=number of revs, per minute. 

Example: Required, the horsepower of a two- 
cycle motor of Ay 2 inches bore and stroke, with 
a speed of 900 revolutions per minute. 

Answer: The square of the bore multiplied 
by the stroke is equal to 91.125, which multi¬ 
plied by 900, and divided by 21,000, gives 3.91 
as the required horsepower. The results given 
by the above examples agree very closely with 
those obtained from actual practice. 

Horsepower, Electrical. One electrical horse¬ 
power is equal to the current in amperes multi¬ 
plied by the electro-motive force or voltage of 
the circuit and divided by 746. 

Let C be the current in amperes and E the 
voltage of the circuit. If E. H. P. be the re¬ 
quired electrical horsepower, then 



354 


The Automobile Handbook 


EXC 

E.H.P=- 

746 

In practice with motors of small power, 1,000 
watts are necessary to deliver one mechanical 
or brake horsepower at the driving shaft of the 
motor. 

If the actual or brake horsepower of an elec¬ 
tric motor be known, the efficiency of the motor 
may be readily found by the following formula: 

If E be the voltage of the circuit and C the 
current in amperes consumed by the motor, let 
B. H. P be the brake horsepower of the motor 
and e the efficiency of the motor, then 

B.H.P X 746 

e —- 

EXC 

Table 10 gives the electrical horsepower of 
motors with voltage from 20 to 100 volts, and 
current strengths from 10 to 80 amperes. 

The mechanical efficiency of a motor may be 
found by use of the table as follows 

Example: Required the mechanical efficiency 
of a 40-volt, 60-ampere motor, which is rated 
by its maker as of 3.25 horsepower—the motor 
when under full load using 80 amperes. 

Answer: Reference to the column in the table 
corresponding to 40 volts and 60 amperes gives 
3.22, while the 80 ampere column gives 4.29. 
Then 3.22 divided by 4.29 gives 0.75, or 75 per 
cent, as the mechanical efficiency of the motor. 




The Automobile Handbook 


355 


Ignition Systems. 

Ignition. In order that an explosive motor 
may operate economically, and with the highest 
percentage of efficiency, it is absolutely neces¬ 
sary that two objects shall be attained, viz.: A 



Coil and Timer Ignition With Storage Battery 

correct mixture of the gasoline and air, and that 
this mixture be correctly ignited at the proper 
time. 

































356 


The Automobile Handbook 



Fig. 155 


Coil and Timer With Dry Cells. A, Switch. B, 
Dry Cells. C, Condenser. D, Timer. E, Con¬ 
tacts. F, Armature. G, Core of Coil. H, Pri¬ 
mary Winding. I, High Tension Winding. J, 
Spark Plug. 



Fig. 156 

Coil Vibrator Principle. A, Core of Coil. B, Arma¬ 
ture of Coil Magnet. C, Adjusting Screw. D, 
Trembler Blade. E, Contacts. 
















































The Automobile Eandhe k 


357 



Spring. C, Trembler Blade. D, Holding Screw. 
E, Contact Bridge. F, Contact Blade. \i, Lock¬ 
ing Screw. 








































358 


The Automobile Handbook 



Connecticut Storage Battery Ignition Wiring 


ftftrTlON SftHTOl 



Circuits Through Remy Battery Ignition System 








































































The Automobile Handbook 


359 


Induction Coil. Induction is the process by 
which a body having electrical or magnetic 
properties calls forth similar properties in a 
neighboring body without direct contact. This 
property is known as self-induction, and is 
caused by the reaction of different parts of the 
same circuit upon one another, due to varia¬ 
tions in distance or current strength. The cur¬ 
rent produced by an induction coil has a very 
high electro-motive force, and hence great 
power of overcoming resistance. 


r 


v ——' 

SWITCH “ + BATTER* 



---- y 

SWITCH + -BATTERY 

INDUCTION COIL 


Fig. 160. 

If a current of electricity be caused to flow 
through a straight conductor forming a part of 
a closed electric circuit, lines of force, com¬ 
monly called magnetic whirls or waves, are in¬ 
duced in the air and rotate around the conduc¬ 
tor. 

If the current of electricity be flowing in the 
circuit and through the straight conductor from 










360 The Automobile Handbook 

right to left, as shown in the upper view in Fig. 
160, the lines of force or magnetic whirls will 
rotate around the conductor from left to right, 
or in the direction of the hands of a clock. On 
the other hand, if the conditions be reversed 
and the current flows from left to right the lines 
of force or magnetic whirls will rotate from 
right to left, as shown in the lower view in Fig. 
160. The direction of rotation of these lines 
of force or magnetic whirls may be positively 
determined by the use of a galvanometer, an 
electric testing instrument having a needle simi¬ 
lar in appearance to that of an ordinary com¬ 
pass. Upon placing this instrument in the 
path of the lines of force and making and 
breaking the battery circuit by means of the 
switch, the needle of the galvanometer will be 
deflected from its zero point in the direction of 
the rotation of the lines of force. If the direc¬ 
tion of the flow of the electric current through 
the circuit be changed by reversing the poles of 
the battery, the needle of the galvanometer will 
be deflected from its zero point in the opposite 
direction. Whether these lines of force or mag¬ 
netic whirls rotate continuously around the wire 
has not been demonstrated. They rotate with 
sufficient force to be tested by the galvanometer 
only until the electric current in the closed 
circuit has reached its maximum value after 
closing the circuit; that is to say, only during 
the infinitesimal space of time required by the 
current to reach its full value or power. 


The Automobile Handbook 


361 


If, instead of a straight conductor, a loop of 
insulated wire, in the form of a circle, be until- 
ized for the passage of the current, as at A and 
B in Fig. 161, the lines of force will still rotate 
around the wire as shown, their direction being 
dependent on the direction of the electric cur¬ 
rent. If the electrical circuit be provided with 



Fig. 161 


a current reverser, or device for changing the 
battery connections in the circuit from positive 
to negative and vice versa, the lines of force can 
be made to rotate rapidly first in one direction 
and then in the other, as indicated in Fig. 160. 

Suppose this loop of insulated wire be com¬ 
posed of a great‘number of turns, it then be- 
















362 


The Automobile Handbook 


comes a coil or closed helix, and as all the lines 
of force cannot pass between the turns of the 
electrical conductor forming this helix they 
must pass completely through the helix instead 
of rotating around a single loop, as at A and B, 
Fig. 161. If the current flows through the con¬ 
ductor in the direction indicated by the ar¬ 
rows, at C in Fig. 161, and over and around the 
coil in the direction shown, the lines of force 
will flow through the coil towards the observer, 
and complete their path or circuit through the 
air, returning into the coil at the opposite end. 
If the current be reversed and flow around the 
coil in the direction of the hands of a clock, the 
lines of force will flow through the coil in the 
opposite direction, that is, away from the ob¬ 
server, as at D, Fig. 161. 

This form of coil or closed helix may he des¬ 
ignated as the primitive form of an electro¬ 
magnet. When forming part of a closed elec¬ 
tric circuit it possesses the property of magnet¬ 
izing a bar of wrought iron placed within it. 
If a short round bar of wrought iron be placed 
a short distance within the coil, and the battery 
circuit be closed, the iron bar will, if the cur¬ 
rent is sufficiently strong, be sucked or drawn 
into the center of the coil, and a considerable 
effort will be required to withdraw it. 

The object of the bundle of soft iron wires, 
which form the core of any form of spark coil, 
is to increase the magnetic effect of the lines of 


The Automobile Handbook 


363 


force or magnetic flux, or rather to reduce the 
resistance to their passage through the coil. 

As has been previously stated, when a current 
of electricity flows through a conductor of wire 
forming a coil or closed helix, lines of force are 
induced and flow through, and also around the 
exterior of the coil. In a like manner, when the 
electric circuit is broken, the lines of force sud¬ 
denly reverse their direction, and travel through 
the coil with a tremendous velocity until they 



Principle of Atwater Kent Battery Ignition 


reach a state of neutralization. During this re¬ 
verse travel of the lines of force through the 
coil, a current of electricity is induced in the 
winding of the coil, but in the opposite direction 
to that in which the battery current was flowing. 
The effect of this induced current, which is of 
far greater intensity or pressure than the bat- 












364 


The Automobile Handbook 

















































The Automobile Handbook 365 

tery current which induced it, is to form an arc 
or spark at the breaking point in the circuit. 

Secondary Spark Coil. Fig. 163 shows the 
secondary or jump-spark form of coil. It is 
composed of an iron core and a primary winding 
similar to that described in conjunction with 
Fig. 162, with the addition of an outer winding 
of many turns of fine wire. This wire, of very 
small size, is known as the secondary winding, 
varying in diameter from No. 36 to No. 40 B. & 
S. Gauge, and in length from 5,000 to 10,000 
feet. In the drawing the induction coil is 
shown equipped with an electro-magnet make 
and break, or vibrator device, which is the form 
mostly used for ignition purposes. The other 
form, known as the plain jump-spark coil, has a 
mechanically operated make and break device 
attached to the motor to operate the coil. 

The arc or spark produced at the breaking 
point of the electrical circuit in which the pri¬ 
mary winding of the coil is connected is not 
utilized for ignition purposes in this type of coil. 
When the circuit is broken the sudden reaction 
or backward flow of the lines of force or mag¬ 
netic flux in the iron core produce an induced 
current in the secondary winding, hut in the 
opposite direction to that of the battery cur¬ 
rent. This induced current is of so much 
greater intensity and velocity than that induced 
in the primary winding by this same reaction, 
that the arc or spark induced in the secondary 
winding of the coil will jump across a. space 


366 The Automobile Handbook 

from one end of the wire to the other, varying 
from inch to as much as 8 or 10 inches in 
length, dependent upon the length of wire in 
the secondary circuit, the electro-motive force 
of the battery and the frequency of the inter¬ 
ruptions or number of times per minute the 
electric circuit is made and broken. 

Referring to Fig. 163 A is the core, B the pri¬ 
mary winding and C the secondary. The two 
coils are held in place upon the core by the 
w r ashers D. The primary wire B is wound over 
a paper tube E, and the secondary wire C is in¬ 
sulated from the primary wire by a mica insu¬ 
lating tube F. The coil proper is enclosed in a 
wood case G. 

The terminals or binding posts on top of the 
case G are connected with the ends of the sec¬ 
ondary wire 1 and 2. The secondary terminals 
are plainly indicated by the letter S’. In the 
base H of the coil case is the condenser J, an 
essential feature of this form of coil, which 
utilizes the induced primary current to produce 
a greater reactive energy in the secondary 
winding. 

At the right-hand end of the coil and outside 
the casing G is located the electro-magnetic vi¬ 
brator or trembling device, which automatically 
makes and breaks the primary circuit. The 
end 3 of the primary wire is connected with the 
contact screw K through the bracket L. The 
spring M, carried by the bracket N, with screw 
0, is connected with the terminal or binding 


The Automobile Handbook 367 

post P, immediately beneath it, by the wire 6 
through the bracket N. The end 4 of the pri- 
mary wire is connected with another terminal 
or binding post P, at the other end of the base 
of the coil. The condenser J is connected 
across the contact points of the screw E and 
the spring M, by the wires 5 and 6 and screws 
Q and X. The condenser is composed of a num¬ 
ber of sheets of tinfoil V, laid between sheets 
of specially insulated paper I, with the opposite 
end of every alternate sheet of tinfoil projecting 
from the paper insulation, as shown. These 
projecting ends are connected together, and by 
the wires 5 and 6 to the contact screw K and 
spring M, respectively, as previously described. 

When the coil is connected in, or forms part 
of a closed electric circuit by means of the ter¬ 
minal or binding posts P, on the base of the 
coil, the current flows through the primary 
winding B. This instantly produces a high de¬ 
gree of magnetism in the core A, and the pole- 
piece T of the core extension R becomes strongly 
magnetic and attracts the iron button W of the 
spring M. This draws the spring M away from 
the end of the screw K, and in consequence 
breaks the electric circuit. This results in the 
demagnetizing of the pole-piece T and the con¬ 
sequent return of the spring M to its normal 
position in contact with the end of the screw K. 
So long as the electric circuit remains closed 
this operation is repeated at a very high rate 
of speed. The effect of this continuous opera- 


368 The Automobile Handbook 

tion of the coil is to produce an intermittent 
current in the secondary winding of high inten¬ 
sity and velocity. If wires are placed in the 
holes in the small terminals or binding posts on 
the top of the coil and brought within a short 
distance of each other, a stream of sparks will 
pass from one wire to the other in a peculiar zig¬ 
zag manner and emit a loud, crackling noise, 
accompanied by a peculiar odor, caused by the 
formation of ozone through the electro-chemical 
action of the spark. 

Under ordinary circumstances the arc or 
spark Which occurs on the breaking of the con¬ 
tact between the platinum points of the screw 
K and spring M would not be utilized, but by 
means of the condenser in the base, which is 
connected to these parts; as before described, 
the static charge of electricity generated by this 
action is stored in the condenser. When the 
contact is again made this stored electric energy 
is given up or discharged by the condenser and 
flows through the primary winding of the coil 
in connection and in the same direction as the 
battery current and increases the magnetic ef¬ 
fect of the core A enormously. 

The construction and operation of the con¬ 
denser is fully described under the heading 
Condenser. It should be understood that this 
is one of the most important elements of the 
ignition system, whether battery or magneto 
type, and its care should never be neglected if 
efficient ignition is desired. 


The Automobile Handbook 


369 


Ignition—Timing. In timing the ignition of 
a motor one should base his operations on one 
particular cylinder, and this should be the most 
accessible one. Let it be assumed that a me¬ 
chanic is required to test or correct the timing 
of a four-cylinder, four-cycle vertical engine. 
He would have to know the order in which the 
cylinders fired, and how to find the firing center 
of No. 1 cylinder. As the operation of the 
valves on most motors may be readily seen, the 
firing center and the order in which the cylin¬ 
ders fire can be easily learned from the action 
of either set. For instance, if on turning the 
motor over slowly the intake valve of No. 1 
cylinder opens and closes, then that of No. 3 
cylinder, and following No. 3 that of No. 4 op¬ 
erates, the mechanic need go no further, for he 
knows that the engine fires 1-3-4-2. The ex¬ 
haust valves, of course, may be used in the same 
way. However, if the valves are entirely en¬ 
closed, as on the Winton cars, open the priming 
or relief cocks, and beginning with cylinder No. 
1 note the order in which the air is forced out 
through the cocks. There are two rules for 
finding which cylinder is on its firing center, 
that are based on the action of the valves; these 
are as follows: When an exhaust valve is open 
the following cylinder is about to fire. When 
an intake valve is open the previous cylinder is 
about to fire. One very simple method of find¬ 
ing the firing center of a cylinder is to open 
the priming cocks of all the cylinders but one, 


370 


The Automobile Handbook 


turn the motor over slowly till compression is 
encountered, open the cock, insert a stiff wire 
till it rests on the piston head, then carefully 
bring the piston to the top of its stroke. The 
cylinder will then be on its firing center. When 
the firing center, and the order in which the cyl¬ 
inders fire are known, all that remains to be 
done in timing an engine is to set the revolving 
segment of the commutator or distributer so 
that a spark will occur in the proper cylinder 
when the spark control lever is advanced about 
one-third or, with the spark control lever fully 
retarded, and the piston about y 2 to 1 inch 
down on the explosion stroke, set the segment 
so that it just begins to make contact. 

Many troubles arise from faulty or defective 
insulation. 

A wire placed too close to an exhaust-pipe 
invariably fails after a time, owing to the insu¬ 
lation becoming burnt by the heat of the pipe. 

A loose wire hanging against a sharp edge 
will invariably chafe through in course of time. 

If the insulation of the coil breaks down it 
cannot be repaired on the road, it should be re¬ 
turned to the makers. A slight ticking is 
usually audible inside the coil when this occurs. 

All wires where joined together should be 
carefully soldered, the joints being afterwards 
insulated with rubber or prepared tape. Never 
make a joint in the secondary wires. See that 
all terminals are tightly screwed up. When 
connecting insulated wire, the insulation must 


The Automobile Handbook 


371 


be removed, so that only the bare wire is at¬ 
tached. Wires sometimes become broken, and 
being loose make only a partial contact. 

Battery terminals frequently become cor¬ 
roded ; they should be covered with vaseline, 
and require periodical cleaning. See that all 
connections at the battery are clean and bright. 

The porcelain of the spark plug may be 
cracked and the current jumping across the 
fracture. The points may be sooty and require 
cleaning. They may be touching and require 
separating, or they may be too far apart. The 
usual distance between the points is about one 
thirty-second of an inch, which is approxi- 
nately the thickness of a heavy business card. 

Clean all oil and dirt from the commutator. 
Most commutators are so placed as to give the 
maximum possible opportunity to collect oil 
and dirt. They should always be provided with 
a cover. 

In course of time dry or storage batteries 
will become weak or discharged. Always carry 
an extra set. 

Spanners, oil-cans, tire-pumps, etc., have been 
known to get on the top of the batteries, 
thereby connecting the terminals together and 
causing a short-circuit. 

The platinum contacts of the coil may be¬ 
come corroded. They should be cleaned with a 
small piece of emery cloth or sandpaper. 


372 


The Automobile Handbook 


Ignition, Atwater Kent. This device is de¬ 
signed to draw from a battery, as nearly as 
possible, only the electrical energy necessary 
to ignite the charge, and to keep the batteries 
until the energy remaining in them is too small 
to produce an effective spark. Its principal 
constituent parts are, a jump-spark coil and 
condenser, a primary contact maker, the time 
of which may be advanced or retarded, and a 
high tension distributer. Its distinguishing 
features are— 

a. But one spark is made for each ignition. 

b. The primary contact, rupture of which 
produces the spark, is exceedingly brief, no 
longer in fact than is actually required to build 
up the magnetism in the core of the spark coil. 

c. The duration of this contact is independ¬ 
ent of the engine speed in the same way that 
the contact of the ordinary coil vibrator is. 

d. Contact is made and broken mechanically 
through a shaft driven by the engine, conse¬ 
quently a spark may be obtained from a bat¬ 
tery that is too weak to operate a vibrator. The 
mechanism by which the instantaneous primary 
contact is produced is similar to a snap contact 
produced by a small spring-controlled hammer 
pulled out of position by a ratchet on the shaft. 
The ratchet has as many teeth as there are cyl¬ 
inders, and runs at the camshaft speed. When 
used with a two-cycle engine, it runs at the 
crankshaft speed if there are four cylinders. If 
there are two cylinders, it runs at half the en- 


The Automobile Handbook 373 

gine speed and the ratchet has four teeth. The 
ordinary commutator is not used in connection 
with it, but a driving connection must be made 
from the crankshaft or camshaft to the vertical 
shaft of the spark generator itself, which is 
mounted on the back of the dashboard. 

The Atwater-Kent system consists of three 
parts: 1, The unisparker, which combines the 
special form of contact-maker, which is the 
basic principle of this system, and a high ten¬ 
sion distributor. 



Atwater Kent Timer Before Moving Lever 

2, The coil, which consists of a simple pri¬ 
mary and secondary winding, with condenser— 
all imbedded in a special insulating compound. 
The coil has no vibrators or other moving parts. 

3, The ignition switch. 

The operation of the unisparker is shown in 
Figs. 164 to 167. This consists of a notched 
shaft, one notch for each cylinder, which ro- 


374 


The Automobile Handbook 


tates at one-half the engine speed, a lifter or 
trigger which is pulled forward by the rotation 
of the shaft and a spring which pulls the lifter 
back to its original position. A hardened steel 
latch and a pair of contact points complete the 
device. 



Fig. 165 

Atwater Kent Timer Before Lever Escapes 

The figures show the operation of the con- 
tact-maker very clearly. It will be noted that 
in Fig. 164 the lifter is being pulled forward 
by the notched shaft. When pulled forward as 
far as the shaft will carry it, Fig. 165, the 
lifter is suddenly pulled back by the recoil of 
the lifter spring. In returning it strikes 
against the latch, throwing this against the con¬ 
tact spring and closing the contact for a very 
brief instant—far too quickly for the eye to 
follow the movement, Fig. 166. 


The Automobile Handbook 


375 


Fig. 167 shows the lifter ready to be pulled 
forward by the next notch. 

Note that the circuit is closed only during 
the instant of the spark. No current can flow 
at any other time, even if the switch is left 
“on” when the motor is not running. 

By means of the distributor, which forms the 
upper part of the unisparker, the high-tension 
current from the coil is conveyed by the ro¬ 
tating distributor block, which seats on the end 
of the unisparker, to each of the spark plug 
terminals in the order of firing. 



Fig. 166 

Atwater Kent Timer With Contacts Closed 

Where the lighting and starting battery is 
used for ignition, two wires from the ignition 
system should run directly to the battery ter¬ 
minals. They should not be connected in on any 
other branch circuit. 


376 


The Automobile Handbook 


The automatic type is cylindrical in shape 
and consists of a pressed steel casing with a 
hard rubber cap, the latter forming the base 
of the high-tension distributor. The device is 
mounted on a shaft which is driven at half the 
speed of the crankshaft. Within the casing is 
located the mechanism, consisting of the gov¬ 
ernor which automatically controls the advance, 
the circuit breaker and high-tension distributor. 



Atwater Kent Timer With Contacts Re-opened 

At the bottom of the casing is the. governor, 
a modification of the centrifugal type which 
consists of two pairs of weights, each pair be¬ 
ing pivoted together at their centers, and two 
double arm brackets. When the shaft starts 
to revolve, the weights extend away from the 
center and the arms change their angular re¬ 
lation in direct proportion to the- speed of the 
driving shaft. 


The Automobile Handbook 377 

In order that the weights will not move away 
from the center too easily and give too great 
an advance to low speeds, the brackets carry¬ 
ing the springs are so arranged that the weights 
have to act against them when obeying the im¬ 
pulse of centrifugal force, and 'moving away 
from the axis of rotation. Virtually each 
weight is a bell-crank lever with one point of 
connection pivoted to the arm and the other 
point of connection pivoted to the weight. The 
four weights thus give four bell-crank levers 
working in the same direction at the same time 
against the four respective springs. 

In timing with automatic advance the piston 
.in No. 1 cylinder should be raised to high 
dead center, between compression and power 
strokes, then, with the clamp which holds the 
unisparker loose, the unisparker should be 
slowly and carefully turned backwards, or 
counter clockwise (contrary to the direction of 
rotation of the timer-shaft), until a click is 
heard. This click happens at the exact instant 
of the spark. Now clamp the unisparker tight, 
being careful not to change its position. 

Now remove the distributor cap, which fits 
only in one position, and note the position of 
the distributor block on the end of the shaft. 
The terminal to which it points is connected to 
No. 1 cylinder. The other cylinders in their 
proper order of order of firing are connected to 
the other terminals in turn, keeping in mind the 
direction of rotation of the timer shaft. 


378 The Automobile Handbook 

When timed in this manner the spark oc¬ 
curs exactly on “center” when the engine is 
turned over slowly. At cranking speeds the 
governor automatically retards the spark for 
safe starting, and as the speed increases, the 
spark is automatically advanced, thus requir¬ 
ing no attention on the part of the driver. 

The first operation in timing the hand ad¬ 
vance unisparker is to crank the engine until 
the piston of No. 1 cylinder is on high dead 
center between the compression and power 
strokes. 

The unisparker is then placed on the shaft, 
the advance rod from the steering post being 
connected to the lug on the side of the uni¬ 
sparker, which is provided for that purpose. 

The position of the spark advance lever on 
the steering wheel sector should be within % 
inch of full retard, and the connecting levers 
should be such as to give the unisparker a 
movement of at least 45 degrees to 60 degrees 
for the full range of spark advance. 

After the spark lever is connected up and the 
unisparker is in position it should be left loose 
at the driving gear, and, with the motor on 
dead center as above directed, the shaft of the 
unisparker should then be turned forward or 
in the same direction as that in which the timer 
shaft normally rotates, until a click is heard, 
at which point it should be set by tightening 
the driving connection. 

The contact points are the only adjustable 


The Automobile Handbook 379 

feature of the unisparker. These points should 
never touch when engine is at rest and the 
space between them should vary from 1/100 
to 1/64 of an inch, depending upon the strength 
of the batteries, spark, heat required, etc. The 
spark can be made hotter by decreasing the dis¬ 
tance, and current can be economized by in¬ 
creasing it. Once or twice a season these con¬ 
tacts should be examined and should be kept 
flat and bright by means of a small file or 
emery cloth on a stick. The proper adjustment 
when starting with new batteries is about 1/32 
of an inch, if dry cells are used. If storage 
battery is used, it may be necessary to reduce 
this a little. At intervals of six or eight hun¬ 
dred miles of service as the batteries decrease 
in strength, these contacts should be closed from 
a quarter to a half turn, or until regular fir¬ 
ing is obtained. Do not attempt under any cir¬ 
cumstances to adjust the tension of the springs. 

Frequently when high-tension wires are run 
from the distributor to the spark plugs through 
metal or fibre tubing, trouble is experienced 
with missing and back-firing, which is due to 
induction between the various wires in the tube. 
This trouble is especially likely to happen if 
the main secondary wire from the coil to the 
center of the distributor runs through this tube 
with the spark-plug wires. 

Wherever possible, the distributor wires 
should be separated by at least y 2 inch of space 
and should be supported by brackets or insu- 


380 The Automobile Handbook 

lators rather than run through a tube. In no 
case should the main distributor wire be run 
through a conduit with the other wires. 

If irregular sparking is noted at all plugs, 
examine first the battery and connection there¬ 
from. If the trouble commences suddenly, it 



Connecticut Igniter Head 


is probably due to a loose connection in the 
wiring. If gradually, the batteries may bei 
weakening or the contact points may require 
attention. See that the contacts are clean and 
bright, and also that the moving parts are not 
gummed with oil or rusted. 

















The Automobile Handbook 381 

Ignition, Connecticut. The Connecticut au¬ 
tomatic igniter system, Fig. 168, produces a 
single spark upon a break occurring in the pri¬ 
mary circuit which, though being closed, has 
energized a coil. This break is effected in the 
igniter by means of a cam revolving against a 
breaker arm. The high tension spark is dis¬ 
tributed in the same instrument. The igniter 
is mounted on a vertical shaft running at half 
engine speed irrespective of the number of 



Connecticut Breaker Mechanism 

cylinders. The breaker arm is insulated from 
the base. This provides a metallic circuit; or 
in other words, no engine ground need be uti¬ 
lized in the primary or battery circuit, as the 
primary winding is insulated from the second¬ 
ary ground in the coil. In this case there is 
no possibility of the ignition being affected 
through grounding or shorts in any other cir- 





382 The Automobile Handbook 

cuit of the car, such as disarrangement in light¬ 
ing or starting systems. 

The igniter may be taken apart and reas¬ 
sembled without the aid of any tools. The dis¬ 
tributor case can be removed by unsnapping the 
two spring clips on the side, thus exposing the 
distributor arm carrying the carbon brush, 
Fig. 169, which can be slipped off the shaft. 



Connecticut Distributor Rotor 

Then remove cotter pin passing through shaft 
and the dust proof cover carrying the upper 
bearing can be taken off and the breaker box 
complete, Fig. 170, can be lifted from the shaft. 
As the shaft is not disturbed the timing is in 
no way affected when the igniter is reassembled 
on the shaft. 


















The Automobile Handbook 


383 


The system is not recommended for use on 
dry cells except as an emergency, but is de¬ 
signed to operate from a storage battery 
charged by a dynamo. 

The automatic switch of the Connecticut 
automatic igniter system is a feature that is 
individual to this system and unique in igni¬ 
tion apparatus. Its function is to kick off the 
switch should the primary circuit be closed an 
unwarranted length of time, as in the case of a 
car being left with the switch on the engine 
stopped. This will prevent the draining of 
batteries. 

Another purpose is to protect the ignition 
wiring should a disarrangement occur in the 
lighting or starting circuit and an excessive 
and destructive amount of current be introduced 
into the ignition circuit. 

The circuit is closed in the automatic switch 
through contacts of the plunger type. These 
plungers are held in contact by a slotted lock¬ 
ing plate. This plate is released by the “off” 
button on the switch; or in cases of prolonged 
or excessive flow of current, by a vibrating 
magnetic release thermostatically effected. The 
construction is such that no amount of outside 
vibration or jar can in any way affect the lock¬ 
ing plate. 

This automatic “kick off” is accomplished 
thermostatically and is a mechanism that has 
been employed for many years in telephone 
switches. 


384 The Automobile Handbook 

To time the igniter, turn the engine over, 
with peteocks open, until the piston of the first 
cylinder has reached the top of the compres¬ 
sion stroke. Now advance the spark lever on 
the steering wheel about three-quarters of the 
way. Remove distributor cap, then set the 
igniter on driving shaft with set screws loose, 
connect advance lever, turn huh of igniter on 
shaft in direction of rotation until contact points 
are just open, which is the point at which the 
spark takes place, then tighten the hub set 
screws. Replace the distributor cap, carefully 
noticing which segment of the distributor the 
brush is opposite, for this is the connection to 
the spark plug of No. 1 cylinder. Connect 
up the balance of the spark plugs in their fir¬ 
ing order. After connecting all wires you are 
then ready to try out the ignition. Before 
cranking, fully retard your spark lever. To 
suit individual requirements, it may be neces¬ 
sary to slightly advance the igniter hub if 
greater speed is required, or slightly retard it 
for very slow speed. 

This igniter is completely housed and pro¬ 
tected. Little care is required to keep it in 
working condition. About every four or five 
thousand miles the distributor cap should be 
removed and wiped out. On the ball-bearing 
igniter, the distributor arm should be with¬ 
drawn and one or two drops and no more of 
good oil injected into the hole in the end of 
the shaft which carries the distributor arm. 


The Automobile Handbook 385 

This will lubricate the lower ball-bearing. No 
other parts need oiling. Care should be taken 
to see that oil does not reach the contact points. 
On the plain bearings or self-lubricating type, 
the bearings require no attention whatever. 

The contact points will probably require no 
attention until run at least ten thousand miles 
and in some cases they may operate for over 
thirty thousand miles without attention. 

The points do not require refiling or clean¬ 
ing even though they may be very rough and 
irregular, but when they become so badly 
burned as to cause missing they should then be 
renewed, in which case proceed as follows: 

Remove the distributor cap and arm, discon¬ 
nect advance lever and wires, remove cotter pin 
in igniter shaft, then spring washer and fibre 
washer, and lift the housing from its shaft. 

The contact adjustment screw will be noticed 
under the dust ring, it being locked from turn¬ 
ing by a hexagon nut on the screw inside near 
the end. Care should be taken to see that this 
nut is tightened up snugly after making a re¬ 
placement or adjustment. When it is necessary 
to adjust these points they should be set so 
that when the roller rests on the point of the 
cam, they open about the same as a magneto 
interrupter. It is not necessary, however, to 
make this adjustment as accurately as on a 
magneto. The adjustable contact screw can 
be removed by taking off the lock-nut and then 
screwing it back out of the housing. 


386 


The Automobile Handbook 


The contact on the breaker arm is riveted 
into it and a complete new arm is necessary in 
making a replacement. 

This arm can be readily removed by taking 
out the small cotter pin in the end of the stud 
on which it moves, remove small fibre washers 
and the arm can then be lifted out. 

When replacing the arm on the stud before 
putting the cotter pin in place, be sure and re¬ 
place the little fibre washers which rest on the 
top of the arm just under the little cotter pin 
and the fibre washer on the stud in the bottom 
of the cup. 

Ignition, Delco. The Delco system of bat¬ 
tery ignition makes use of a combined breaker 
and distributor usually mounted on, and driven 
from, the lighting dynamo or motor-dynamo. 
In some installations the ignition unit is placed 
by itself, but the construction and operation is 
the same in either case. 

The distributor and timer are driven through 
a set of spiral gears attached to the armature 
shaft or its extension. The distributor con¬ 
sists of a cap or head of insulating material, 
carrying one high-tension contact in the center, 
with similar contacts spaced equi-distant about 
the center, and a rotor which maintains con- 
stant communication with the central contact 

The rotor carries a contact button which 
sends the secondary circuit to the spark plug 
in the proper cylinder, 


The Automobile Handbook 


387 


Beneath the distributor head and rotor is the 
timer, Fig. 171, which is provided with a screw 
in the center of the shaft, the loosening of which 


D C 



Fig. 171 


Delco Ignition Head Breaker. A, Cam Holding 
Screw. B, Battery Current Contacts. C, 
Breaker Cam. D, Resistance Wire Spool. E, 
Cam Contact Levers. M, Dynamo Current Con¬ 
tacts. 


allows the cam to be turned in either direction 
to secure the proper timing, turning in a clock¬ 
wise direction to advance and counter-clock¬ 
wise to retard. 













388 


The Automobile Handbook 


The spark occurs at the instant the timer 
contacts are opened. 

The adjustment screw must always be set 
down tight after the cam is adjusted. 

The same weight which operates the arm on 
the regulating resistance also operates the auto¬ 
matic spark control. In addition to the auto¬ 
matic spark control, a manual spark control 
is provided, which is operated by the lever on 
the steering column, and is connected to the 
lever at the bottom of the motor generator. 
The manual spark control is for the purpose of 
securing the proper ignition control for vari¬ 
able conditions, such as starting, differences in 
gasoline and weather conditions. The auto¬ 
matic control is for the purpose of securing the 
proper ignition control necessary for the varia¬ 
tions due to speed alone. 

The resistance unit is a coil of resistance wire 
wound on a porcelain spool. Under ordinary 
conditions it remains cool and offers little re¬ 
sistance to the passage of current. If for any 
reason the ignition circuit remains closed for any 
considerable length of time, the current passing 
through the coil heats the resistance wire, in¬ 
creasing its resistance to a point where very lit¬ 
tle current passes, and insuring against a waste 
of current from battery and damage to the igni¬ 
tion coil and timer contacts. When the arm 
that cuts the regulating resistance into the 
shunt field circuit is at the top position (that 
is, at high speeds), the resistance unit is cut 


The Automobile Handbook 389 

out of the ignition circuit. This increases the 
intensity of the spark at high speeds. 

To time ignition: Fully retard the spark 
lever. Turn the engine so that upper dead 
center on flywheel is about one inch past dead 
center with No. 1 cylinder on the firing stroke 
Loosen screw in center of timing mechanism 
and locate the proper lobe of the cam by turn- 
ing until the button on the rotor comes under 
the high tension terminal for No. 1 cylinder. 
Set this lobe of the cam so that when the back 
lash in the distributor gears is rocked forward 
the timing contacts will be open, and when the 
back, lash is rocked backward the contacts 
will just close. Tighten screw and replace rotor 
and distributor head. 

If the motor fires properly on the “M” but¬ 
ton, but not on the U B” button, the trouble 
must be in the wiring between the dry cells or 
the wires leading from the dry cells to the com¬ 
bination switch, or depleted dry cells. 

If the ignition works on the “B” button and 
not on the “M” button, the trouble must be 
in the leads running from the storage battery 
to the motor-generator, or the lead running 
from the rear terminal on the generator to the 
combination switch, or in the storage battery 
itself, or its connection to the frame of the car. 

If both systems of ignition fail and the sup¬ 
ply of current from both the storage battery 
and dry cells is ample, the trouble must be in 
the coil, resistance unit, timer contacts or con- 


390 The Automobile Handbook 

denser. This is apparent from the fact that 
these work in the same capacity for each sys¬ 
tem of ignition. 

The following directions for upkeep apply in 
a general way to the “M” or “Mag” igni¬ 
tion on all of the Delco systems, but do not 
apply to the dry battery ignition. 

The contact points are of tungsten metal, 
which is very hard and requires a very high tem¬ 
perature to melt. These should be kept clean and 
smooth on the faces. This can be done by hold¬ 
ing in a vice and using fine emery cloth held 
underneath a flat file. They should be so ad¬ 
justed that when they are open they are apart 
ten-thousands of an inch and the contact arm 
should move about fifteen-thousands of an 
inch after the contacts close. 

The most common causes of contact trouble 
are due to the following: (1) Resistance 
unit shorted out, resulting in excessive current 
through the contacts, especially at low speeds. 
(2) Abnormally high voltages due to run¬ 
ning without the battery or with a loose con¬ 
nection in the battery circuit. (3) A broken 
down condenser. 

The distributor head should be properly lo¬ 
cated, that is with the locating tongue of the 
hold-down clip in the notch on the distributor 
head. The head should be kept wiped clean 
from dust and dirt and in some cases it is 
advisable to lubricate this head with a small 
amount of vaseline. 


The Automobile Hatidbook 391 

The rotor should be kept free from dust and 
dirt and the rotor button polished bright The 
rotor button should be fully depressed before 
putting on the distributor head to make sure 



the spring will allow the button to go down to 
the proper level and not subject it to undue 
pressure on the distributor head. 






























392 The Automobile Handbook 

Remy Battery System. This make of igni¬ 
tion equipment is furnished in two principal 
types, one of which might be called “ magneto 
type” and the other one a “vertical ignition 
head.” 

The magneto type equipment, Fig. 172, bears 
a very close resemblance to the breaker and dis¬ 
tributor end of a separate unit magneto, being 
composed of a distributor having terminals for 
the spark plug leads and below the distributor 
a breaker exactly similar in construction to that 
with magnetos. In connection with this unit 
a two-way switch is used, giving either dry bat¬ 
tery or generator as a source of ignition current. 
To transform the current to one of high-ten¬ 
sion a separate coil is used. 

This coil differs from ordinary coil construc¬ 
tion inasmuch as both ends of the primary wind¬ 
ing are insulated, so that, in the event of a 
ground occurring in the lighting or starting cir¬ 
cuits, the ignition will be unaffected. The coil 
is provided with a safety gap as a further 
means of protection. 

The coil is wound for six volts and is to be 
used in connection with a storage battery or 
with five dry cells. The coil is to be mounted 
on the crankcase within 6 or 8 inches of the 
breaker points as the condenser is incorporated 
in the coil and not on the generator. A special 
top plate is provided to securely hold coil in 
position. 

The circuit breaker platinum points may be 


The Automobile Handbook 


393 


inspected by removing the Bakelite housing 
cover. The points should have a smooth, clean, 
flat surface at all times. The break, or gap, of 
these points should be from 15 to 20 thou¬ 
sandths of an inch. The circuit breaker may, 
if desired, be removed without the aid of tools. 

The high-tension current is distributed to the 
spark plug cables by means of a hard carbon 
brush making contact with distributor segments. 
Neither distributor nor brush will require any 
attention whatsoever. 



Remy Vertical Ignition Timer 


An oiler is provided for the distributor shaft, 
—only a few drops of light oil every one thou¬ 
sand miles will suffice. 

The use of spark plugs which permit of the 
points being adjusted to a definite gap is recom¬ 
mended. The gap between the points should be 
from 20 to 25 thousandths of an inch. 




394 The Automobile Handbook 

If the motor misses when runfiing idle or 
pulling light, the plug gaps should be wider. 
If motor misses at high speed or when pulling 
heavy at low speed, the plug gaps should be 
made closer. 

The vertical ignition head consists of a com¬ 
bined breaker and distributor mounted in one 
case, Fig. 173, and adapted to be driven from a 
vertical shaft usually on or near the lighting 
dynamo. 

Some of these distributors have a manual ad¬ 
vance for the spark, while some are built with 
a mechanism which automatically advances the 
spark to meet the requirements of the engine 
upon which it is installed. 

The high-tension current is distributed to the' 
spark plug leads by a segment which revolves 
close to, but does not touch, the pins in the dis* 
tributor head. 

Either iridium-platinum, tungsten or silver is 
used in the contact points, the choice depending 
upon which is best suited to the installation. 

The coil furnished with this system has a spe¬ 
cial ventilating base which may be bolted se¬ 
curely to the engine frame. Its current con¬ 
sumption is limited by a resistance located on 
top of the coil and which is in series with the 
primary winding. 

The metal base of the coil makes an electrical 
connection with the engine or car frame for one 
side of the secondary winding. Therefore, it is 
very important before mounting the coil to see 


The Automobile Handbook 395 

that all foreign matter, such as dirt, grease, 
paint, etc., is removed from the place where the 
coil is to be mounted. It is also very important 
that the base of the coil be fastened down se¬ 
curely at all times. 

The switches furnished with this equipment 
are arranged to reverse the direction of current 
flow through the circuit breaker each time the 
ignition is used. 

It is absolutely necessary that the ignition 
switch be placed in the “off” position when the 
engine is not running. If it is left in the “on” 
position, current from the storage battery will 
be dissipated in the ignition coil which, if con¬ 
tinued, will exhaust the battery. 

By an insulated system is meant one in which 
the circuit breaker is not grounded. By glanc¬ 
ing at the wiring diagram it will be seen that 
the circuit from the switch around through the 
breaker box and back to the switch again is not 
grounded, and that the switch reverses the di¬ 
rection of the current flow through this circuit 
at each quarter turn. 

If the insulation is worn off any one of the 
wires and the copper touches any of the metal 
parts of the car, a short circuit will result which 
will either render the system inoperative by 
burning out a fuse or will discharge the bat¬ 
tery. A periodical inspection should be made of 
all wiring to see that it is not rubbing or chafing 
on any of the metal parts of the car and that all 
connections are tight and secure. 


396 The Automobile Handbook 

The contact screw should be adjusted with 
the wrench furnished with the system, so that 
the maximum opening of the points is .020 to 
.025 inch, or the thickness of the piece riveted 
upon the side of the wrench. The rebound 
spring should be at least .020 of an inch from 
the breaker arm when the points are at their 
maximum opening. 

To obtain the best results the spark-plug gaps 
should be adjusted to .025 of an inch. 

Ignition, Westinghouse. Dual ignition is 
obtained in the Westinghouse system; that is, 
the battery is an independent source of supply, 
as well as the generator operating with the bat¬ 
tery, while the interrupter, ignition coil and 
distributer are common to both. 

The interrupter is so constructed that the 
period of contact is practically the same at any 
speed. The spark voltage, therefore, does not 
fall off at high speeds, but is practically the 
same at all speeds. 

Automatic spark advance is a feature of the 
Westinghouse generator. The automatic ad¬ 
vance works over a range of 45°. Provision is 
made for manual operation also, and it is recom¬ 
mended that this be connected up, but the spark 
lever need not ordinarily be touched after the 
original adjustment, the automatic device taking 
care of all adjustments in running. 

The interrupter is mounted on the generator 
shaft and contacts are operated by a centrifugal 
device that automatically adjusts the spark ad- 


The Automobile Handbook 39? 

vance to the speed, keeps the period of contact 
nearly constant at all speeds and prevents any 
inequality between the two interruptions that 
occur in succession during each revolution. 



Pig. 174 

Westinghouse Ignition and Lighting Dynamo 

The ignition outfit consists, in addition to the 
lighting system and storage battery, of a dis¬ 
tributer and an interrupter, which are made a 
part of the generator, Fig. 174, and an ignition 
coil and switch. The ignition coil transforms 
the six volts of the battery up to the high ten¬ 
sion required for the spark plugs. The inter¬ 
rupter closes and then opens the ignition cir¬ 
cuit at each half revolution of the generator 
shaft, and the distributer directs the high-ten¬ 
sion current to each of the spark plugs in suc¬ 
cession. 












398 The Automobile Handbook 

The operation of the ignition system, includ¬ 
ing the interrupter and distributer, ignition coil 
and switch, begins with the 11 making’ ’ of the 
primary circuit of the coil when the centrifugal 
weights push down the fibre bumper, allowing 
the interrupter contacts to close, Fig. 175. Then 
the weight moves off the fibre bumper, allowing 
the contacts to suddenly separate or open, when 
a high voltage is induced in the secondary of 
the ignition coil and directed by the distributer 



Westiiighouse Ignition Breaker, Low Speed Po¬ 
sition 

to the proper spark plug, causing a spark. As 
the speed of the engine increases, the weights 
are thrown out from the center and automatic¬ 
ally advance the time of closing or opening the 
interrupter contacts, and hence advance the 
spark, Fig. 176. At the same time, due to their 
shape, they keep the contacts closed during a 
greater part of the revolution when running at 
high speed; this makes the period of contact 





















The Automobile Handbook 399 

practically the same at all speeds and prevents 
the spark voltage from falling off at high 
speeds. 

To connect the ignition system to the circuit, 
insert the plug into the ignition switch and 
move the switch handle to the “on” position. 



Westinghouse Ignition Breaker, High Speed Po¬ 
sition 

In inserting the ignition plug pay no attention 
to the position of the brass contact pieces on 
the plug. It is desirable that the contacts will 
average up as often in one as in the other of the 
two possible positions, as this reverses the direc¬ 
tion of the current through the interrupter con¬ 
tacts and greatly increases their life. 

The spark plug should be set with slightly less 
than 1/32 inch between tips for best operation. 
Oily or carbonized plugs will often cause miss¬ 
ing, and if dirty, they should be well brushed 
inside and outside with gasoline and wiped per- 









400 The Automobile Handbook 

fectly dry. A crack in the insulating material 
will, of course, probably lead to failure of spark 
in the cylinder. 

The interrupter stop is adjusted so as to give 
the proper pressure on the bumper. When the 
engine is not running and the weights are in a 
closed position, there should be a space of 3/64 
inch between the bumper lever and the stop. 
After the stop is adjusted, the contact screw 
should be adjusted by means of a wrench, so 
that with the cam lever against the upper stop, 
the contacts are open .005 inch. After setting 
for this separation, tighten the clamping screw 
so that the contact screw is held firmly. Be sure 
that the contacts open up positively and that 
the moving element moves clear up against the 
upper stop when released, with some spring ten¬ 
sion still remaining to hold it in this position. 
See that the contacts are kept free from all oil 
and grit. 

Interrupter weights should turn freely on 
their supporting pins and should also clear the 
centrifugal weight spring support by approxi¬ 
mately .01 inch. They should show no lost mo¬ 
tion between the two interlocking weights. In 
making any readjustments, be careful that when 
the engine is turned over very slowly by hand, 
both weights depress the moving part of the 
interrupter enough to definitely close the con¬ 
tacts, otherwise there will be a tendency to miss 
fire in every second cylinder, especially at low 
speeds and if the contacts are worn more or less. 


The Automobile Handbook 401 

When the weights are in the inner position, 
the springs should just touch the fibre-covered 
pins on the weights without exerting any appre¬ 
ciable pressure over that required to just posi¬ 
tively return the weights to the innermost posi¬ 
tion. If necessary to adjust these springs, al¬ 
ways bend the supporting arms and not the 
springs themselves. 

Distributer brushes should slide freely in 
their holders and the springs should push them 
out so as to extend from the holder about % 
inch when the distributer plate is removed from 
the generator. These brushes should, however, 
be retained firmly by their springs so as to never 
tend to fall completely out of the tubes. Be 
sure that both these brushes are in place in the 
distributer. 

Distributer plate should be kept clean and 
free from carbon dust between brushes and con¬ 
tact surfaces by an occasional wiping. Any 
pitting of the distributer which is in advance 
of the contacts, indicates that the distributer 
gear is set one tooth or so too far back against 
the direction of its rotation. This may cause 
intermittent firing of the cylinders at the higher 
speeds, with consequent loss of power. The 
gear is set correctly at the factory, and if this 
setting is not disturbed the above trouble will 
not be encountered. 

The distributer gear is meshed with the pinion 
on the generator shaft so that the mark at the 
edge of the gear lines up with the tooth of the 


402 The Automobile Handbook 

pinion that is slightly beveled. In coupling the 
generator to the engine, place the piston of 
cylinder No. 1 on dead center at the end of the 
compression stroke. Remove the distributer 
plate and turn the generator back so that the 
line of the distributer brushholder block corre¬ 
sponds with the line on the end bracket. Couple, 
the engine and generator shafts while in this 
position. 



Westinghouse Vertical Ignition Head 

The Westinghouse vertical ignition unit can 
be used for ignition from storage batteries or 
plain lighting generators, Fig. 177. This set 




























The Automobile Handbook 


403 


contains interrupter, spark coil and condenser, 
and distributer, all in one unit. One wire from 
the battery or generator to the ignition unit and 
one wire to each spark plug are all that are 
required. 



Westinghouse Vertical Ignition Wiring 

The interrupter, located at the lower end of 
the set, has the same type of circuit-breaker as 
that on the Westinghouse ignition and lighting 

























































404 


The Automobile Handbook 


generators, but no automatic spark advance fea¬ 
ture. It can be used equally efficiently for either 
direction of rotation without charge. The in¬ 
terrupter is enclosed by a spring collar which 
can be readily removed for inspection or adjust¬ 
ment of the contacts. The collar makes a tight 
joint and is clamped by a screw which prevents 
it from slipping. See wiring diagram, Fig. 178. 

The Westinghouse Ford vertical ignition unit 
is made up of four essential parts, namely, the 
interrupter, the condenser, the induction coil, 
and the distributer, all included in one case. 

The operation of the' interrupter can be ob¬ 
served by loosening the thumbscrew and sliding 
upward the loose section of the insulation case, 
which forms the interrupter cover. 

With the ignition switch turned to the “on” 
position and the engine turning over, each seg¬ 
ment of the interrupter cam in turn passes on 
and off the fibre bumper. As each cam passes 
off the bumper, the interrupter contacts close, 
closing the circuit from the battery to the pri¬ 
mary winding of the induction coil. Then as 
they pass on the bumper, the contacts are 
opened, suddenly opening the circuit, thus in¬ 
ducing a high voltage in the secondary of the in¬ 
duction coil. This voltage is directed by the 
distributer on the top of the ignition unit to 
the proper spark plug, causing a spark at the 
spark gap of the plug inside the cylinder, and 
igniting the charge therein. 

The contact screw should be adjusted with a 


The Automobile Handbook 405 

screwdriver so that, with the cam against the 
bumper, the contacts are open .008 inch. 

If the contacts show pitted or irregular sur¬ 
faces they should be smoothed up with a very 
fine file, making certain that the surfaces come to¬ 
gether squarely after adjustment has been made. 

Ignition, Magneto Type. Magneto ignition 
makes use of a separately mounted machine 
having its own armature and field magnets (per¬ 
manent magnets) and being driven from the 
engine. A magneto always consists of a rotat¬ 
ing member, this being a shuttle wound arma¬ 
ture in most cases, or simply pieces of iron in 
the inductor type. This rotating member, 
through the change in the path of the lines of 
force from the magnets, produces a current in 
a coil separate or on the armature in the 
shuttle wound form, or mounted separately in 
the inductor magneto. This current rises from 
zero to its maximum voltage twice for each 
revolution of the magneto shaft, one impulse 
flowing in one direction through the windings 
and the next one (on the other half revolution) 
flowing in the opposite direction. The current 
from a magneto always reverses its direction in 
this way and is, therefore, an alternating cur¬ 
rent. The current from a lighting dynamo does 
not reverse its direction and is a direct current. 
For this reason no magneto can ever be used for 
charging a storage battery, a battery requiring 
current that always flows in one direction 
through the circuit. 


406 The Automobile Handbook 

Combined with the armature and the perma¬ 
nent steel magnets that provide the field for 
the magneto is a breaker mechanism that inter¬ 
rupts the flow of current through the circuit 
whenever a spark is desired, and also a dis¬ 
tributor that carries the contacts for delivering 
the high-tension current through the wires that 
lead to the spark plug in the cylinder that is 
ready to fire. While the details of construction 
of magnetos differ as described in the following 
pages, all types contain the parts described 
above. A shuttle wound armature with a break¬ 
er mounted on its shaft is shown in Fig. 179. 



The breaker may take any one of several 
forms, a commonly used construction being 
shown in Fig. 180. The circuit is completed 
through the contacts A, one of which is solidly 
mounted, and the other one attached to the mov¬ 
able arm B. The arm carries a fibre block that 
strikes a stationary cam when it is revolved on 
the armature shaft, and inasmuch as the arm is 
pivoted, the contacts are separated to interrupt 
the circuit and cause a spark to come from 
the winding of the high tension coil of the sys- 






The Automobile Handbook 407 

tem. The fine winding that forms the high ten¬ 
sion coil may be wound around outside of the 
armature winding on the shuttle type, or may 
be mounted in a housing separate from the 
magneto. With the high tension coil on the 
armature, the magneto is self-contained and pro¬ 
duces a spark without outside parts, being called 
a true high tension magneto. Those magnetos 
using outside coils generate the current in their 



Fig. 180 

Magneto Breaker 


armature and send it through the heavy wind¬ 
ing of the separate induction coil, or trans¬ 
former coil. This separate coil has also a fine 
wire winding in which the high tension spark 
plug current is induced by the breaking of the 
circuit through the heavy wire when the break¬ 
er on the magneto opens. 

The system known as “single ignition,” when 
using a magneto, comprises a true high tension 









408 The Automobile Handbook 

machine from which wires lead to the spark 
plugs. The only other wire required is one to 
the switch that will allow the driver to stop the 
production of sparks by connecting the arma¬ 
ture winding to the frame of the car, or ground¬ 
ing it. No other source of current is provided 
with single ignition. 

“Double ignition” provides a true high-ten¬ 
sion magneto, as described, and in addition, a 
complete, and entirely separate, battery, timer 
and coil system with a separate set of spark 
plugs and wiring. 

“Dual ignition” uses a magneto similar to 
the single ignition high-tension type, but pro¬ 
vides an additional breaker and induction coil 
through which current may be led from a set 
of dry cells or a storage battery, thus providing 
a source of current other than that of the 
magneto armature when desired for starting or 
emergency use. 

“Transformer coil ignition” makes use of a 
magneto that produces in its armature, or by 
inductor action, a current of low voltage that 
is led to a separately mounted transformer, or 
induction coil. The coil is connected by wires 
to the breaker and distributor on the magneto. 

How to Remove and Replace a Magneto. 
When about to replace or remove a magneto it 
is well to see that all separable parts are prop¬ 
erly marked, and if not, mark them. This may 
be done with a center punch, cold chisel, letters 
or numerals. In Fig. 181 is shown the guide 


The Automobile Handbook 409 

marks generally used in connection with a high- 
tension magneto of a four-cylinder motor. The 
center punch marks C, on the Oldham coupling 
such as is usually employed on the magneto 
shaft between the magneto and its driving gear, 
serve as a guide in replacing the magneto. All 
that is necessary in replacing a high-tension 
magneto so marked on a four-cylinder, four¬ 
cycle motor is to see that the marks are directly 
opposite each other; but in two or six-cylinder 
motors, where the crankshaft and the armature 
of the magneto do not run at the same speed, 
care must be taken either not to move the 
crankshaft while the magneto is off or to check 
up the timing before it is replaced. In the 
same illustration is shown the method of mark¬ 



ing the timing gears. These marks are made 
with a cold chisel and are generally present in 
up-to-date construction. 











410 


The Automobile Handbook 



Fig. 182 

Figs. 182 and 183 

Bosch High Tension Magneto, Type “DU”. 1, 

Armature End Plate for Primary Winding Con¬ 
nection. 2, Breaker Fastening Screw. 3, 
Breaker Contact Block. 4, Breaker Disc. 5, 
Long Platinum Contact Screw. 6, Short Plati¬ 
num Contact Screw. 7, Flat Spring for Breaker 
Lever. 8, Breaker Lever. 9, Condenser. 10, 
Collector Ring for High Tension Current. 11, 
High Tension Carbon Brush. 12, Carbon Brush 
Holder. 13, Conductor Bar Terminal. 14, Con¬ 
ductor Bar. 15, Distributor Brush Holder. 16, 
Distributor Carbon Brush. 17, Distributor Plate. 
18, Central Contact on Distributor. 19, Brass 
Segment. 20, Terminal for Spark Plug Wire. 
21, Steel Breaker Cam. 22„ Dust Cover. • 24, 
Grounding Terminal. 25, Distributor Block 
Holding Spring. 116, Breaker Timing Lever. 
117, Breaker Cover. 118, Conducting Spring for 
Grounding Terminal. 119, Breaker Cover Hold¬ 
ing Spring. / 

























































The Automobile Handbook 


411 


Bosch Magnetos. The Bosch high tension 
magneto, Fig. 182, generates its own high-ten¬ 
sion current directly in the armature winding 
and without the use of a separate coil or other 
apparatus. Apart from the cables connecting 
the magneto to the plugs, the Bosch high-ten¬ 
sion magneto requires no external connections. 



Pig. 183 


The armature carries two windings. The pri¬ 
mary consists of a few layers of heavy wire and 
the secondary of a great number of layers of 
fine wire. One end of the primary winding is 
grounded on the armature core, and the live end 
is brought out to a circuit-breaking device. The 
grounded end of the secondary winding is con- 






412 


The Automobile Handbook 


nected to the live end of the primary winding 
so that one is a continuation of the other. 

During certain portions of the rotation of the 
armature the primary circuit is closed, and the 
variations in magnetic flux have their effect in 
inducing an electric current in it. When the 
current reaches a maximum, which will occur 
twice during each rotation of the armature, the 
primary circuit is broken, and the resulting ar¬ 
mature reactions produce a high-tension current 
of extreme intensity in the secondary winding. 
This current is transmitted to a distributer by 
means of which it passes to the spark plug of 
the cylinder that is in the firing position. 

The magneto interrupter, Fig. 183, is fitted 
into the end of the armature shaft which is 
taper-bored and provided with a key-way. The 
interrupter is held in position by a fastening 
screw, and may easily be removed. In replacing 
it, care should be taken that the key fits into 
the key-way and that the fastening screw is 
well tightened. 

Twice during each revolution of the armature 
the primary circuit closes and opens, this being 
effected by the interrupter lever coming in con¬ 
tact with a steel segment, which is supported 
on the interrupter housing. When the magneto 
interrupter lever is not being acted upon by the 
steel segment, the platinum points are in con¬ 
tact, thus closing the primary circuit. Then 
as the armature rotates farther and the inter¬ 
rupter lever again comes in contact with a seg- 


The Automobile Handbook 


413 


ment, the platinum points (interrupter con¬ 
tacts) open and thus interrupt the primary cir¬ 
cuit. At the opening of the contact the ignition 
spark occurs instantaneously. 

The distance between the platinum points 
when the magneto interrupter lever is fully de¬ 
pressed by one of the steel segments must not 
exceed 1/32 inch. This distance may be adjusted 
by means of a long platinum screw, and should 
be in accordance with the steel gauge that is 
pivoted to the adjusting wrench. 



Fig. 184 

High and Low Tension Circuits of Bosch Magneto 


The connections of the magneto, Fig. 184, 
consist of a high-tension cable from the dis¬ 
tributor to each spark plug, and a low-tension 
cable leading to the switch. 

In order to protect the insulation of the arma¬ 
ture and of the current-carrying parts of the 

























414 The Automobile Handbook 

apparatus against excessive voltage, a safety 
spark gap is arranged on the dust cover. It 
consists of a short pointed brass rod set on the 
dust cover, and a second pointed brass part sup¬ 
ported a short distance from it in the center of 
the steatite cover of the housing. The insulated 
point is connected into the secondary circuit, 
and should there be any interference with the 
circuit normally provided through the spark 
plug the safety spark gap provides a point of 
discharge. 

If a spark is observed passing in the safety 
spark gap it is an indication that there is an 
interruption in the regular secondary circuit, 
and the cause should be at once investigated. 

A simple test for the magneto is to disconnect 
the grounding cable from grounding terminal 
and also to disconnect the spark plug cables. 
The motor should then be cranked briskly, and 
the safety spark gap closely observed. If sparks 
are seen at this point, it is an absolute indica¬ 
tion that the magneto is in proper operating 
condition. If no sparks are observed it will be 
necessary to make sure that the primary cir¬ 
cuit is properly interrupted by the magneto in¬ 
terrupter. Holding spring must be moved side¬ 
ways, interrupter housing cover taken off, and 
it must be ascertained whether fastening screw 
is well tightened. After this it should be ob¬ 
served whether the platinum points are in con¬ 
tact when the steel cams are not acting on the 
magneto interrupter lever, also whether they 


The Automobile Handbook 415 

separate the correct distance, 1/25th inch, when 
the interrupter lever is resting on one of the 
steel cams. Otherwise the distance must be 
adjusted by means of the platinum screw. The 
platinum contacts must be examined and any 
oil and dirt removed; in case the contacts are 
uneven (but only then) they must be smoothed 
with a fine flat file. If, after continued use, the 
platinum contacts are completely worn down, 
the two platinum screws must be renewed. 

The Bosch dual magneto is of the standard 
Bosch type, and produces its own sparking cur¬ 
rent, which is timed by the revolving inter¬ 
rupter. The parts of this interrupter are car¬ 
ried on a disk that is attached to the armature 
and revolves with it, the segments that serve 
as cams being supported on the interrupter 
housing. 

In addition, the magneto is provided with a 
steel cam having two projections, which is built 
into the interrupter disk. This cam acts on a 
lever that is supported on the interrupter hous¬ 
ing, the lever being so connected in the battery 
circuit that it serves as a timer to control the 
flow of battery current through the coil. 

It is obvious that the sparking current from 
the battery and from the magneto cannot be led 
to the spark plugs at the same time, and a fur¬ 
ther change from the magneto of the indepen¬ 
dent form is found in the removal of the con¬ 
ducting bar between the collecting ring and the 
distributer. The collecting ring brush is con- 


416 The Automobile Handbook 

nected to the switch and a second wire leads 
from the switch to the terminal that is centrally 
located on the distributer. 

When running on the magneto, the sparking 
current that is induced thus flows to the dis¬ 
tributer by way of switch contact. When run¬ 
ning on the battery the primary circuit of the 
magneto is grounded, and there is, therefore, 
no production of sparking current by the mag¬ 
neto; it is then the sparking current from the 
coil that flows to the distributer connection. It 
will thus be seen that of the magneto and bat¬ 
tery circuits the only parts used in common are 
the distributer and the spark plugs. 

The end plate of the coil housing carries a 
handle by which the switch may be operated. 
By means of this switch either the magneto or 
the battery may be employed as the source of 
ignition current, and in its operation the entire 
coil is rotated within the housing. The inner 
side of the stationary switch plate is provided 
with spring contacts that register with contact 
plates attached to the base of the coil. 

For the purpose of starting on the spark, a 
vibrator may be cut into the coil circuit by 
pressing the button that is seen in the center of 
the end plate. Normally, this vibrator is out 
of circuit, but the pressing of the button brings 
together its platinum contacts and a vibrator 
spark of high frequency is produced. It will 
be found that the distributer on the magneto is 
then in such a position that this vibrator spark 


The Automobile Handbook 417 

is produced at the spark plug of the cylinder 
that is performing the power stroke; if mixture 
is present in this cylinder ignition will result 
and the engine will start. 



Fig. 185 

Bosch Dual System Wiring Diagram 


The dual system requires four connections be¬ 
tween the magneto and the switch, Fig. 185; 
two of these are high tension and consist of wire 
No. 3 by which the high-tension current from 
the magneto is led to the switch contact, and 
wire No. 4 by which the high-tension current 
from either magneto or coil goes to the distribu¬ 
tor. Wire No. 1 is low tension, and conducts 
the battery current from the primary winding 
of the coil to the battery interrupter. Low-ten¬ 
sion wire No. 2 is the grounding wire by which 
the primary circuit of the magneto is grounded 









































418 


The Automobile Handbook 


when the switch is thrown to the “off” or to 
the battery position. Wire No. 5 leads from the 
negative terminal of the battery to the coil, and 
the positive terminal of the battery is grounded 
by wire No. 7; a second ground wire No. 6 is 
connected to the coil terminal. 



Method of Setting Armature of Bosch Magneto 

The timing of the Bosch Dual Magneto is 
identical with the standard type. The dual 
magneto is so arranged that the battery inter¬ 
rupter breaks its circuit approximately 10 de¬ 
grees later than the magneto interrupter; this 
feature gives the full timing range of the mag¬ 
neto. With the timing lever fully retarded and 
the switch on the battery position, the battery 
spark will occur after the piston has passed 









The Automobile Handbook 


419 


dead center and is moving on the power stroke. 
The possibility of a back kick is thus eliminated. 

The magneto should be placed in position on 
the bed plate or pad provided for it, the bolts 
or straps being properly secured; the driving 
gear or coupling, however, should be loose on 
the armature shaft. ' The dust cover, which is 
an aluminum plate located under the arch of 
the magneto, should then be removed, and this 
is accomplished according to the design of the 
various types of magnetos. 

The engine should now be cranked until one 
of the pistons, preferably that of cylinder No. 1, 
is at the top of the compression stroke. With 
the engine in this position, the armature should 
be rotated by hand in the direction in which it 
will be driven until it is approximately in the 
position illustrated in Fig. 186. The setting of 
the armature is determined by the dimension 
marked E, Fig. 186, as follows: 

* 4 DU3 ’ ’ Model 4.11 to 14 mm. 

4 4 DU4 ’ ’ Model 4.13 to 15 mm. 

4 4 DU6 ’’ Model 4.16 to 20 mm. 

44 DU3”Model4. 8to 11 mm. 

4 4 DU4 ’’ Model 4.10 to 13 mm. 

4 4 DU6 ’’ Model 4.12 to 16 mm. 

With-the armature held in the proper posi¬ 
tion, the gear or coupling should be secured. 
The greatest care should be exercised to prevent 
the slipping of the armature during this opera¬ 
tion. 

In the fully enclosed magneto it is unneces- 








420 The Automobile Handbook 

sary to remove either the interrupter housing 
cover or the distributer plate in order to deter¬ 
mine the setting of the instrument, or to locate 
the distributer terminal with which contact is 
made. 

The magneto having been bolted into posi¬ 
tion, the crankshaft is to be turned to bring 
one of the pistons, preferably that of cylinder 
No. 1, to the firing position for full advance. 

The armature is then rotated until the figure 
“1” can be seen through the window in the 
face of the distributer plate. The cover of the 
oilwell on the distributer end of the magneto 
is then to be raised, and the armature is to be 
turned a few degrees in one direction or the 
other until the red mark on one of the dis¬ 
tributer gear teeth is brought to register with 
the red marks on the side of the window located 
between the two oil ducts. 

The magneto is then in time for the full ad¬ 
vance position, and the gear or coupling is to be 
secured to the armature shaft. Great care 
should be taken not to disturb the position 
either of the crankshaft or the armature shaft 
when fitting the driving member. 

Bosch Enclosed Types. In the “DU” dual 
magneto, the current is led from the collector 
ring connection to the coil and back to the 
distributer terminal that is located in the cen¬ 
ter of the distributer plate. In the enclosed 
dual magneto, this central terminal is 'elimi¬ 
nated, and the current is led internally to the 


The Automobile Handbook 421 

distributer from a connection on the shaft end 
of the magneto. To expose this terminal, the 
shaft end bonnet should be removed, which is 
done by withdrawing the two screws in its lower 
flange, and sliding the bonnet backward. The 
terminal will then be seen to be a vulcanite post, 
with a boss that projects through a hole in the 
bonnet. In the top of this post are two vertical 
holes, in the bottom of each of which is a screw. 
These screws are to be withdrawn. The ends 
of the high-tension wires No. 3 and No. 4 lead¬ 
ing to the coil are then to be cut off square, 
and after being led through the hole in the bon¬ 
net, are to be pressed to the bottoms of the 
slanting holes in the boss. The pointed screws 
are then to be replaced in the vertical holes, and 
in being driven home they will pierce the cables 
(and their insulation) and make the required 
connections. It is essential to use a screwdriver 
of the proper size, for a tool with too large a 
blade will inevitably crack the vulcanite. Great 
care must be taken to apply the, screwdriver to 
the screws vertically in order to avoid cracking 
the vulcanite by side pressure. When the con¬ 
nections are made the bonnet is to be replaced. 

Bosch Upkeep and Care. It will be noted 
that the press button on the coil is arranged to 
set in either of two positions, which are indi¬ 
cated by an arrow engraved on its surface, or 
projecting from its edge. When this button is 
in such a position that the arrow is pointing on 
the word “run” a single contact spark will be 


422 The Automobile Handbook 

produced when the engine is cranked, or when 
the engine is running with the switch in the 
battery position. Under all ordinary conditions 
the button position should invariably be used. 

When the engine is chilled, however, or under 
poor mixture conditions, starting can frequently 
be facilitated by pressing down the button and 
turning it slightly to the right so that the arrow 
is pointing to the word “start .’’ This will lock 
the vibrator in circuit, and a shower of vibrator 
sparks will be produced in place of the single 
contact spark. 

The platinum points of the magneto inter¬ 
rupter should be kept clean and smooth and so 
adjusted that they are open about 1/64 inch, 
or the thickness of the gauge attached to the ad¬ 
justing wrench, when the magneto interrupter 
lever is wide open on one of the rollers or seg¬ 
ments. It should not be necessary to clean or 
readjust these points oftener than once a season, 
and it is not advisable to readjust them until 
their condition # and the missing of the engine 
show it to be absolutely necessary. 

Each coil is stamped with the voltage of the 
battery current for which it is wound, and if 
this voltage is not exceeded the platinum con¬ 
tacts of the battery interrupter will not require 
attention for long periods. When this battery 
interrupter lever is being operated by the roll¬ 
ers or segments, the platinum points should be 
slightly wider open than the contact points of 
the magneto interrupter—the proper distance 
being about 1/50 inch. 


The Automobile Handbook 423 

If the magneto is at fault, all the cables and 
terminals should be examined for improper con¬ 
nections. The coil and battery system may then 
be disconnected by removing the wires from 
terminals Nos. 3 and 4 of the magneto, and with 
a short piece of wire magneto terminal No. 3 
may be connected directly with magneto ter¬ 
minal No. 4. This will conduct the high-tension 
current induced in the magneto direct to the 
distributer. The grounding wire should then 
be disconnected from terminal No. 2 of the 
magneto. With this arrangement it should be 
possible to start the engine on the magneto, and 
it will be necessary to follow this plan should 
any accident happen to the coil. 

To ascertain if the magneto is generating cur¬ 
rent, the grounding wire should be disconnected 
from terminal No. 2 on the magneto, and the 
high-tension wire should be disconnected from 
the collecting ring terminal No. 3. If the engine 
is then cranked briskly a spark should appear 
at the safety spark gap that is located under 
the arch of the magnets on the dust cover, 
provided the magneto is in proper condition. 
The grounding wire should then be reconnected 
to terminal No. 2, and the engine cranked. If 
no spark appears at the safety spark gap, the 
trouble may be determined as a leakage of the 
primary magneto current to ground by chafed 
insulation, incorrect connections, or an injury 
to the switch parts. 

The coil may be tested by disconnecting wire 


424 The Automobile Handbook 

No. 4 from the magneto and throwing the switch 
to the battery position, operating the press but¬ 
ton with terminal No. 4 3/16 inch from the 
metal of the engine. If the coil is in good con¬ 
dition, a brilliant spark should be observed. If 
the spark does not appear the test should be re¬ 
peated with wire No. 3 disconnected. If the 
fault persists the coil body may be removed 
from the housing by withdrawing the holding 
screw that is located close to the supporting 
flange; the switch should then be unlocked and 
the end plate given a quarter revolution. This 
will release the bayonet lock and the coil body 
may then be withdrawn to permit the inspection 
of the switch contacts both of the coil and of 
the stationary switch plate. It may be that the 
spring contacts are bent or otherwise in bad 
condition. The withdrawing of the coil body 
and its handling should be performed with ex¬ 
treme care. No work should be done on the coil 
in the way of withdrawing screws, etc., and if 
the inspection does not disclose the fault the 
coil should be returned to its housing and the 
whole returned to the makers or to one of their 
branches. 

Bosch “NU” Magneto. Like other Bosch 
high-tension magnetos, the type “NU4,” Fig. 
187, generates its own high-tension current di¬ 
rectly in the magneto armature (the rotating 
member of the magneto) without the aid of a 
separate step-up coil, and has its timer and 
distributer integral. The distinct gear-driven 


The Automobile Handbook 425 

distributor common to other types has been 
omitted in the “NU4” magneto, and in its stead 
is a double slipring combining the functions of 
current collector and distributor. 

The armature winding is composed of two 
sections: one, primary, or low tension, consist¬ 
ing of a few layers of comparatively heavy 
wire, and the other, secondary, or high tension, 
consisting of many layers of fine wire. 




Fig. 187 

Bosch High Tension Magneto, Model “NU” 

The beginning of the primary winding is in 
metallic contact with the armature core, and 
the other, or live, end is connected by means of 
the interrupter fastening screw to the insulated 
contact block supporting the long platinum 
screw on the magneto interrupter. The inter¬ 
rupter lever, carrying a short platinum screw, is 
mounted on the interrupter disc which, in turn, 
is electrically connected to the armature core. 
The primary circuit is completed whenever the 





































426 The Automobile Handbook 

two platinum interrupter screws are in contact 
and interrupted whenever these screws are sepa¬ 
rated. The separation of the platinum screws is 
controlled by the action of the interrupter lever 
as it bears against the two steel segments se¬ 
cured to the inner surface of the interrupter 
housing. The high-tension current is generated 
in the secondary winding only when there is an 
interruption of the primary circuit, the spark 
being produced at the instant the platinum in¬ 
terrupter screws separate. 

The secondary winding is insulated from the 
primary, and the two ends of the secondary are 
connected to two metal segments in the slipring 
mounted on the armature, just inside the driv¬ 
ing shaft end plate of the magneto. The slip¬ 
ring has two grooves, each containing one of 
the two metal segments. These segments are set 
diametrically opposite on the armature shaft, 
that is, 180 degrees apart, and insulated from 
each other, as well as from the armature core 
and magneto frame. 

The four slipring brushes which are part of 
the secondary circuit are supported by two 
double brush holders, one on each side of the 
driving shaft end plate, each holder carrying 
two brushes so arranged that each brush bears 
against the slipring in a separate groove. Upon 
rotation of the armature, the metal segment in 
one slipring groove makes contact with a brush 
on one side of the magneto at the same instant 
that the metal segment in the other slipring 


The Automobile Handbook 


427 


groove comes into contact with a brush on the 
opposite side of the magneto. The marks 1 and 
2 appearing in white on both brush holders in¬ 
dicate pairs of brushes receiving simultaneous 
contact, those marked 1 constituting one pair, 
and those marked 2 the other. 

A spark is caused at two plugs simultane¬ 
ously. It is important to note that as two of 
the four slipring brushes receive contact simul¬ 
taneously and each is connected by cable to the 
spark plug in one of the cylinders, the secondary 
circuit always includes two plugs, and the spark 
occurs in two cylinders simultaneously. 

After removing one of the brush holders to 
permit observation of the slipring, the armature 
shaft is rotated in the direction in which it is 
to be driven, until the beginning of the metal 
.slipring segment is visible in the slipring groove 
corresponding to Fig. 1 of the brush holder 
which has been removed. With that done, the 
cover of the magneto interrupter housing is to 
be removed to expose the interrupter. The 
armature shaft should then be further rotated 
until the platinum interrupter screws are just 
about to separate, which occurs when the inter¬ 
rupter lever begins to bear against one of the 
steel segments of the interrupter housing. 

The armature should be held in that position 
while the magneto drive is connected to the 
engine, due care being taken that the piston of 
No. 1 cylinder is still exactly on top dead center 
of the compression stroke. 


428 


The Automobile Handbook 


After the brush holder and interrupter hous¬ 
ing cover have been replaced the installation is 
completed by connecting the cable of one of the 
brushes, marked 1, with cylinder No. 1, Fig. 188, 
and the other with cylinder No. 4; the remain¬ 
ing two cables, leading from the brushes, marked 
2, must be connected with cylinders Nos. 2 
and 3. 



Fig. 188 

Wiring Connections for Bosch Magneto, Model 
“NU” 


Dixie Magneto. The Mason principle on 
which the Dixie magneto operates is shown in 
Fig. 189. The magnet has two rotating polar 
extremities, N S, which are always of the same 
polarity, never reversing. These poles are in 
practical contact with the inner cheeks of the 
permanent magnet M, all air gaps being elimi¬ 
nated. Together with the U-shaped magnet, 
they form a magnet with rotating ends. 











































The Automobile Handbook 429 

At right angles to the rotating poles is a field 
consisting of pole pieces F and G, Fig. 190, 
carrying across their top the core C and the 
windings W. When N is opposite G, the mag¬ 
netism flows from pole N on the magnet to G 
and through the core C to F. 



Fig. 189 

Dixie Magneto Principle 
In Fig. 191 the pole N has moved over to F 
and the direction of the flow of magnetism is 
reversed; it now flowing from F through C to 
G. The rotating poles do not reverse their 
polarity at any time, consequently the lag due 
to the magnetic reluctance in this part is elimi¬ 
nated. 

The magneto has a rotating element consist¬ 
ing of two pieces of cast iron with a piece of 
brass between them, but no armature of the 
usual form, the revolving generating element 
being shown in Fig. 192. The pieces N S are 
separated by the brass block B and correspond 
to the pieces N S in Figs. 189, 190 and 191. The 
generating windings are carried on a small coil 
placed across the upwardly projecting ends of 
two pole pieces. 












430 


The Automobile Handbook 


The core of the coil A, Fig. 193, is stationary, 
and the inner end G of the primary winding 
P is grounded on the core. Q indicates the 
metal frame of the machine, which is put to- 



Fig. 190 Fig. 191 

Dixie Magneto Action Reversal of Magnetism 

Through Dixie Magneto 

gether with screws. The condenser R is located 
immediately above the coil and is readily re- 



Rotating Element in Dixie Magneto 


movable. The terminal D is a screw on the 
head of the coil and the wire Z connects di¬ 
rectly to the contact Y of the breaker. The 
breaker contacts are stationary and do not re¬ 
volve as in the armature type. 


























The Automobile Handbook 431 

Fig, 194 shows the high tension circuit. Here 
the end C of the high tension winding goes to 
a metal plate D carried on the upper side A of 
the coil. Against D bears a connection F, which 
is practically one piece with the traveling con¬ 
tact J, which connects to the spark plug- seg¬ 
ment L, the circuit being completed through the 
spark plug, engine frame and frame of magneto 
in the usual manner without brush G. 



Fig. 193 

Low Tension Primary Circuit of Dixie Magneto 

The proper distance between the platinum 
points when separated should not exceed 1/50 of 
an inch, and a gauge of the proper size is at¬ 
tached to the screwdriver furnished with the 
Dixie. 

The platinum contacts should be kept clean 
and properly adjusted. Should the contacts be¬ 
come pitted, a fine file should be used to smooth 
them in order to permit them to come into per¬ 
fect contact. The distributor block should be 














432 The Automobile Handbook 

removed occasionally and inspected for an ac¬ 
cumulation of carbon dust. The inside of the 
distributor should then be wiped dry with a 
clean cloth. When replacing the block, care 
must be taken in pushing the carbon brush into 
the socket. The magneto should not be tested 
unless it is completely assembled, that is, with 
the breaker box, distributor cover and wires in 
position. 



High Tension Circuit of Dixie Magneto 

In order to obtain the most efficient results 
with the Dixie magneto the normal setting of 
the spark plug points should not exceed .025 of 
an inch and it is advisable to have the gap just 
right before a spark plug is inserted into the 
cylinder. The spark plub electrodes may be 
easily set by means of the gauge attached to the 
screwdriver furnished with the magneto. 

Eisemann Magneto. There are two types of 
the Eisemann magneto. First, the low-tension 


















The Automobile Handbook 433 

magneto requiring a transformer to raise the 
voltage of the current; and second, the high 



Eisemann High-Tension Magneto 
tension magneto, which has a double winding 
on the armature and does not require a non¬ 
vibrator coil. 




































434 The Automobile Handbook 

The low tension magneto gives off from 20 
to 40 volts only. One end of the armature 
winding is grounded, the live end passing to 
the insulated contact of the interrupter, which 
is located at the end of the armature shaft. 
From this point the circuit continues to one 
terminal of the primary winding of the coil, 
the other terminal of which is grounded. The 
grounded part of the interrupter, a pivoted le¬ 
ver, is operated by a cam carried on the arma¬ 
ture shaft, and makes and breaks contact with 
the insulated part. The cam is set in such re¬ 
lation to the armature that the breaking of the 
circuit by the interrupter coincides with the 
production of maximum current in the arma¬ 
ture winding. When the interrupter is making 
contact, the magneto current is offered two cir¬ 
cuits by which it may flow to ground, one 
being through the interrupter and the other 
through the primary winding of the coil. The 
resistance of the former being low, the current 
takes that path in preference to the other, 
which is of higher resistance. When the cur¬ 
rent reaches its maximum the cam breaks the 
interrupter circuit, and the only path by which 
the current can then flow to ground is that of¬ 
fered by the primary winding of the coil. This 
sudden and intense flow causes the core of the 
coil to throw out a powerful magnetic field, 
which induces a current in the secondary wind¬ 
ing of from 20,000 to 40,000 volts. This current 
is passed to the proper spark plug through the 


The Automobile Handbook 


435 


medium of a distributer located on the magneto 
and driven by the armature shaft. A condenser 
is connected across the interrupter contacts to 
reduce the sparking as the circuit is broken, 
and to effect a more abrupt change in the mag¬ 
netic field of the coil. 



General Wiring Diagram for Eisemann Magneto 

A later Eisemann magneto is of the high- 
tension type, as shown in Fig. 195, in which A 
is the cam nut; B, steel contact for high-ten¬ 
sion distributer; C, platinum contact for make- 
and-break lever; D, high-tension distributer 
cover; E, nut for adjustable contact screw; 














































436 


The Automobile Handbook 


F, spring for make-and-break lever; G, carbon 
contact for high-tension distributer; H, make- 
and-break -lever; I, low-tension carbon brush; 
K, adjustable platinum contact screw; L, grease 
box for large toothed wheel; M, nut; N, cam; 
0, cable joints; P, distributer plate; Q, metal 
contact; S, screw for spring for make-and- 
break lever; V, high-tension distributer. 



Fig. 197 

Magnetos are made to turn in either direc¬ 
tion, but the magneto once finished turns in one 
direction only, and this direction is indicated 
by an arrow placed on the gear wheel case. 

The spark occurs in one of the cylinders at 
the moment that the contact points are sepa¬ 
rated by the cam. The advance mechanism is 
arranged in three different ways: (1) by means 
of a lever working the make-and-break mechan¬ 
ism (quadrant advance); (2) by means of a 
piston sliding longitudinally, and fitted to the 
























The Automobile Handbook 437 

end of the driving axle (piston advance); (3) 
by rocking the magnets bodily around the ar¬ 
mature (pivoting advance). In all cases a dis¬ 
placement of 45 degrees can be obtained. In 
magnetos with quadrant advance the driving 
spindle is fixed by means of a pin and nut. 

This type of magneto is consequently shorter 
than the one with piston advance. In the lat¬ 
ter case the driving pinion is fixed on a hollow 
spindle. 



The Eisemann dual system consists of a direct 
high-tension magneto and a combined trans¬ 
former coil and switch. The transformer proper 
is used only in connection with the battery; 
the switch is used in common by both battery 
and magneto systems. The magneto is prac¬ 
tically the same as the single ignition instru¬ 
ment. Separate windings and contact breakers 
are used for battery or magneto current. On 
the other hand, parts that are not subject to 
accident, or rapid wear, are used in common. 



















438 


The Automobile Handbook 


A distinctive feature is that the pole pieces 
are of a certain shape, Fig. 198, whereby the 
most extended portion thereof is approximately 
opposite the theoretical axis of the winding 
upon armature core. This construction results 
in the flow of the magnetic lines of force being 
drawn from the extremities of the pole pieces 
towards the center of the core; a large volume 
of the magnetic line of force is thus forced 
through the winding. 



Breaker of Eisemann Magneto 


The make-and-break mechanism, Fig. 199, 
consists of a bronze plate on the back of which, 
and cast in one piece with it, is a cone, fitting 
into the armature shaft, which is bored out 
and provided with a key-way. It moves inside 
of the timing lever and is fastened to the arma- 



















The Automobile Handbook 439 

ture by means of the screw. If this screw is 
extracted the whole mechanism can be removed. 

The primary current is led from the winding 
through the armature shaft to the contact screw 
by the insulated screw, which also serves to hold 
the mechanism to the armature shaft as already 
described. When the armature reaches the cor¬ 
rect position, a lever is lifted by two steel cams 
fastened to the magneto body; the primary cir¬ 
cuit is broken and the current is induced in the 
secondary winding. The beginning of the sec¬ 
ondary winding is connected with the end of the 
primary winding, and the other end, through 
several mediums, finally delivers the spark in 
the cylinder. 

In addition to this the magneto is also fitted 
with the battery circuit breaker, which is mount¬ 
ed at the back of the magneto breaker. It con¬ 
sists of a steel cam, having two projections 
which actuate a steel lever mounted into the 
breaker housing. 

A condenser is built in between the T-shaped 
end of the armature and the bearing. This pre¬ 
vents a spark occurring at the platinum con¬ 
tacts with the consequent pitting and burning, 
when the contact breaker opens, and it also in¬ 
creases the intensity of the spark at the plugs. 

The coil consists of a non-vibrating transform¬ 
er and a switch, which is used in common to 
put either the battery or magneto ignition into 
operation. It is cylindrical in shape, compact, 


440 The Automobile Handbook 

and is placed through the dashboard. The end 
which projects through on the same side as the 
motor has terminal connections for the cables. 
The other end, facing the operator, contains the 
switch and the starting mechanism. The trans¬ 
former proper is used only in conjunction with 
the battery. 

As the spark occurs when the primary circuit 
is broken by the opening of the platinum con¬ 
tacts, it is necessary that the magneto will be so 
timed that at full retard the platinum contacts 
will open when the piston has reached its highest 
point on the firing stroke. To arrive at this, turn 
motor by hand until piston of No. 1 cylinder 
is on the dead center (firing point). Place the 
timing lever of the magneto in fully retarded 
position, then turn armature of magneto until 
No. 1 appears at the glass dial of the distributer 
plate, and make sure that the platinum contacts 
of the magneto are just opening. Fix the driv¬ 
ing medium in this position. 

If no window is seen, turn motor by hand 
until piston of No. 1 cylinder is on dead center 
(firing point), remove the distributer plate from 
the magneto and turn the drive shaft of the 
armature until the setting mark on the distribu¬ 
ter disc is in line with the setting screw above 
the distributer. (For magneto rotating clock¬ 
wise use setting mark R, and for counter clock¬ 
wise use mark L.) With the armature in this 
position the platinum contacts are just opening 
and the metal segment of the distributer disc 


The Automobile Handbook 441 

is in connection with carbon brush for No. 1 
cylinder. The driving medium must now be 
fixed to the armature axle without disturbing 
the position of the latter, and the cables con¬ 
nected to the spark plugs. 

If a spark plug cable becomes disconnected or 
broken, or should the gap in the spark plug be 
too great, then the secondary current has no 
path open to it, and endeavoring to find a 
ground will sometimes puncture the insulation 
of the armature of the coil. To obviate this, a 
so-called safety spark gap is placed on the top 
of the armature dust cover. It consists of pro¬ 
jections of brass with a gap between them. One 
of these is an integral part of the dust cover, 
and therefore forms a ground. The other brass 
part is connected with the terminal H M and 
the secondary Current will jump across the in¬ 
tervening gap above mentioned, thus protecting 
the armature secondary winding and the high 
tension insulations. 

In the coil, this safety gap is placed at one 
end of the core, and hence is not visible. It 
consists of a pointed brass finger, attached to 
one end of the secondary, and pointing towards 
the iron core of the coil. 

The contact points may be cleaned with gaso¬ 
line until the contact surface appears quite 
white, or use a fine file, but very carefully, so 
that the surfaces remain square to each other. 
The gap at the contact points should not amount 
to more than 1/64 inch and, as the contacts 


442 The Automobile Handbook 

wear away in time, they must be regulated now 
and then by giving the screw a forward turn, 
or eventually by renewing. When this platinum 
tipped screw is adjusted, care must be taken 
that the lock-nut is securely tightened in place. 
By loosening the center screw, the whole inter¬ 
rupting mechanism may be taken out, so that 
the replacement of the platinum contacts with¬ 
out removing the apparatus can be easily done 
at any time. The fixing screw of the make-and- 
break is held fast by a lock spring, so that it 
is impossible for this screw to loosen. When it 
is desired to remove this screw, the lock spring 
must first be removed by turning it over the 
head of the screw. Do not forget to put the 
spring in the original position after having fixed 
the make-and-break to the armature. 


a 



Magneto 


The Eisemann automatic advance, Fig. 200, is 
accomplished by the action of centrifugal force- 
on a pair of weights A attached at one end to a 
sleeve B, through which runs the shaft C of the 
magneto, and hinged at the other end to the 
armature. 





















The Automobile Handbook 443 

Along the armature shaft arm run two spiral 
ridges which engage with similarly shaped 
splines in the sleeve. When the armature is 
rotated the weights begin to spread and exert a 
longitudinal pull on the sleeve which in turning 
changes the position of the armature with refer¬ 
ence to the pole pieces. In this way the moment 
of greatest current is advanced or retarded, and 
with it the break in the primary circuit, for the 
segments which lift the circuit breaker and 
cause the break in the primary circuit are fixed 
in the correct position and thus the break can 
only occur at the moment when the current in 
the winding is strongest. On magnetos without 
this advance it is the segments which are moved 
forward or back, as the case may be. As there 
is only one actually correct position for the seg¬ 
ments, every degree away from this weakens 
the spark. 

The spreading of the weights rotates the arma¬ 
ture forward, and advances the spark and the 
resumption, either total or in part, of their 
original position close to the shaft, retards it by 
rotating the armaturfe backward. 

As the timing is accomplished by changing 
the relative positions of armature and motor 
and not those of the segments in the timing level 
which cause the breaking of the circuit, the 
spark is always bound to occur at the moment 
cf greatest current and the apparatus thus 
given as strong a spark at retard as when fully 
advanced. 


444 The Automobile Handbook 

As the speed becomes slower a spring D 
brings the weights together again, so that by 
the time the motor has come to rest the magneto 
is fully retarded, this being the correct position 
for starting. 



Fig. 201 

Magneto Used on the Ford Cars 


In the rear end of the governor housing there 
is a transverse slot into which fits a key, fur- 






















































The Automobile Handbook 445 

nished with each magneto. When this key is 
shoved in as far as it can go the armature is 
fixed in the position where the platinum con¬ 
tacts begin to open. The shaft is held tight in 
the correct position and the coupling may be 
screwed up with the assurance that the magneto 
is correctly set and without danger of damag¬ 
ing the armature. 


446 The Automobile Handbook 

Ford Magneto. The Ford magneto, Fig. 
201, is of a peculiar design, it being constructed 
as an integral part of the flywheel, in which A 
is the support for the magneto coils; BBB, mag¬ 
neto coils; CC, permanent horseshoe magnets; 
DD, the flywheel; E, planetary pinions; F, low 
speed brake band; G, reverse brake band; II, 
disc-clutch for high speed; I, transmission 



brake; J, clutch rocker shaft, and K, high speed 
clutch spring. The permanent magnets, which 
are U-shaped, are bolted to the forward face of 
the flywheel, as shown in Fig. 202. Close in front 
of their outer ends is a series of insulated coils 
mounted in a circle of practically full flywheel 
diameter, with their axes parallel with that of 
the crankshaft. They are supported upon a 
stationary spider, as shown in Fig. 203. As the 
flywheel revolves, this magnet and coil com¬ 
bination, which is similar to that used on some 



The Automobile Handbook 


447 


types of alternating current generators, pro¬ 
duces a current which is used through a four- 
unit current timer to cause the ignition spark. 
The magneto is of the inductor type, the arma¬ 
ture coils being stationary, and the field mag¬ 
nets moved past them. Sixteen separate field 
magnets are used, made of vanadium-tungsten 
steel. They are substantially hoyseshoe shape, 
being secured to the side of the flywheel as illus¬ 
trated in Fig. 203. They are held in place by 
screws at their middle, and by clamps near their 
poles, all screws used for fastening them being 
securely locked in place by wire locks. 

The magnets are so arranged that like poles 
are adjacent to each other, forming a six¬ 
teen pole field magnet crown. Instead of being 
placed close against the flywheel, these mag¬ 
nets are clamped against a ring of non-magnetic 
material (brass for instance), in order to re¬ 
duce leakage of magnetism through the fly¬ 
wheel rim. At their middle these magnets are 
fastened directly to the flywheel, as at this point 
they are neutral, and there can be no leakage. 
A series of sixteen armature coils is carried on 
a coil supporting ring slightly in front of the 
flywheel, as shown in Fig. 202. These coils are 
wound with heavily insulated magnet wire, and 
are so grouped around the supporting ring that 
the winding of adjacent coils is in different di¬ 
rections, one being wound clockwise, and the 
next one counter clockwise. The coils are con¬ 
nected in series, the terminals being brought 


448 


The Automobile Handbook 


out near the top of the casing. As the poles 
of the magnets are located opposite and very 
close to the coils, the magnetic circuits are com¬ 
pleted by the cores of these coils and the coil 
support. There are evidently sixteen electrical 
impulses produced during the revolution of the 
crankshaft and flywheel, although only two im¬ 
pulses are required for the ignition of the mo¬ 
tor, one per stroke. However, as the armature 
circuit is closed only when a spark is wanted, 



Fig. 204 
Herz Magnets 


a current only flows at that period, and there 
is no loss from the other impulses. 

Herz High Tension Magneto. This mag¬ 
neto differs from the regular conventional type 
in that it is cylindrical in shape, due to the em¬ 
ployment of ring-shaped field magnets A—Pig. 
204 instead of the horseshoe type generally 
adopted. The six Herz magnets are in reality 
as many flat steel rings clamped together with 
a polar space, or armature tunnel, C, cut in 




The Automobile Handbook 


449 


them. The ring surfaces are ground with the 
utmost accuracy in order to obtain the best 
magnetic effect when they are all clamped to¬ 
gether. These magnets are mounted on an 
aluminum base S. A second unconventional¬ 



ity is that the usual independent, soft-metal 
pole pieces, which bolt to the ends of the horse¬ 
shoe magnets in the conventional magneto, are 
dispensed with entirely. In the Herz system 
the space C, which accommodates the armature, 






450 


The Automobile Handbook 


is bored out from the magnets A, and in this 
manner sharp angles in the magnet system, 
which invariably result in a leakage of lines of 
force in the magneto, are avoided. The arma¬ 
ture D, Fig. 205, is of shuttle shape, accommo¬ 
dating the low, and high-tension windings E 
within the frame portion of it. So careful has 
the construction of this armature been superin¬ 
tended that there is but 1-10-millimeter air 
space between it and the curved portions of the 
magnets A. The armature revolves on ball¬ 
bearings, mounted in special cages, and is fitted 
with lubricating means sufficient for many 
months’ use. The armature windings consist 
of a primary winding, in which is generated the 
low-tension current and also a secondary wind¬ 
ing in which is generated the induced, or high- 
tension circuit. At one end of the armature, 
and encased in a brass box, is the condenser, F, 
Fig. 205. 

The make-and-break devices for interrupting 
the primary circuit are illustrated in Fig. 205, 
the entire device being a detachable unit, which 
secures to the armature shaft by a key-way and 
feather. This make-and-break mechanism con¬ 
tacts with one end of the primary winding of 
the armature through a small carbon brush, fit¬ 
ted into the contact disk, which presses against 
a ring alongside of the ball race on the arma¬ 
ture. The contact device consists of three 
parts: First, a curved spring G, having a plat¬ 
inum flat contact on one end; a steel block II 


The Automobile Handbook 


451 


carrying an adjustable platinum contact, and 
a small, hard-fiber roller K carried on a pin. 
This roller is set so that if it is given a slight 
push at the edge it tends to move up the in¬ 
cline plane formed by the steel piece H, and in 
doing so pushes against the end of the spring G 
and separates the platinum contacts L. This 



contact-maker revolves bodily with the arma¬ 
ture, and in its rotation the fiber roller K strikes 
upon two steel pr.ojections M—Fig. 206—held 
in the case, thus breaking the circuit at the 
points of maximum induction twice in each rev¬ 
olution, at which time the induced current is 
set up in the secondary winding of the magneto. 

It is scarcely necessary to comment here that 









452 


The Automobile Handbook 


the primary and secondary windings are thor¬ 
oughly insulated from each other, and that, 
with the making and breaking of the primary 
current an induced current is set up in the sec¬ 
ondary winding, which because of the many 
turns of wire in this winding, is of a particu¬ 
larly high voltage. For cutting off the spark 
when desired a terminal is provided on the con¬ 
tact-maker case, which gives a connection by 
means of a spring pressing on the head of a 



Fig. 207 

High-Tension End 


steel screw in connection with the insulated 
end of the primary winding, which thus can 
be short-circuited at will. In advancing or 
retarding the spark, connections are made with 
the ball-ending N, Fig. 206, the contact-maker 
having a 30-degree movement for this purpose. 
The high-tension end of the armature has 
mounted upon it a deeply recessed insulating 
collar, with a metallic sector within it. Upon 
this sector are small carbon brushes for draw- 








The Automobile Handbook 453 

ing off the high-tension current. In Fig. 207 
appears a magneto suitable for a two-cyl¬ 
inder engine with its high-tension terminals 
R located at 90 degrees to each other. To ob¬ 
tain the two sparks the high-tension contact 
piece, orsector is fitted with an insulating col¬ 
lar, which does not go quite half way round, 
and thus makes alternate contact with the two 
carbon brushes R, sending the spark to the re¬ 
spective cylinder. In four-cylinders a distrib¬ 
uter is combined. The safety spark gap is 
located between the high-voltage sector and the 
armature, and if the spark exceeds % inch it 
bridges the insulating collar to the armature. 

Mea Magneto. The most noticeable differ¬ 
ence between the Mea magneto and other stand¬ 
ard forms is that the magnets are bell-shaped 
and are placed horizontally and with their axes 
in line with the armature shaft. This is a dis¬ 
tinct variation from the customary horseshoe 
magnets placed at right angles. This makes 
possible the simultaneous movement of the mag¬ 
nets and breaker instead of the advance and 
retard of the breaker alone. 

It will be seen that, as a result of this con¬ 
struction, the relative position of armature and 
field at the moment of sparking is absolutely 
maintained, and the same quality of spark is 
therefore produced, no matter what the timing 
may be. 

Fig. 208 shows a longitudinal section of a 
four-cylinder instrument. In the bell-shaped 


454 The Automobile Handbook 

magnet 100, having the poles on a horizontal 
line near the driven end of the magneto, rotates 
armature 1 in ball bearings 17 and 18. The 
armature consists mainly of an I-shaped iron 
core, mounted on a spindle, and wound with a 
heavy primary winding of a few turns and a 
light secondary winding of many turns. On 
this armature are also mounted the condenser 
12, the collector ring 4, and the low-tension 



Fig. 208 
Mea Magneto 

breaker 26-39. The latter is built up of a disc 
27, which carries the short platinum contact 33 j 
the other contact point 34 is adjustable and 
supported by a spring 20, which in turn is fas¬ 
tened to the insulated plate 28 mounted on disc 
27. The breaker is actuated by the fibre roller 


















The Automobile Handbook 455 

31 in connection with cam disc 40, which is 
provided with two cams and located inside the 
breaker, being fastened to the field structure. 
In revolving with the armature the roller 
presses against the spring supported part of the 
breaker whenever it rolls over the two cams and 
in this manner opens the breaker twice every 
revolution. Inspection of the breaker points is 
made possible by means of an opening in the 
side of the breaker box, provided at the point 
of the circumference at which the breaker opens. 
The box is closed by a cover 74, supporting at 
its center the carbon holder 47, by means of 
which the carbon 46 is pressed against screw 24. 
This latter screw connects with one end of the 
low tension winding, while the other end is 
connected to the core of the armature. It will, 
therefore, be seen that the breaker ordinarily 
short-circuits the low tension winding and that 
this short-circuit is broken only when the break¬ 
er opens; it will also be apparent that when 
the screw 24 is grounded through terminal 50 
and the low-tension switch to which it is con¬ 
nected, the low-tension winding remains perma¬ 
nently short-circuited, so that the magneto will 
not spark. The entire breaker can be removed 
by loosening screw 24. 

The high tension current is collected from col¬ 
lector ring 4 by means of brush 77 and brush 
holder 76, which are supported by a removable 
cover 91, which also supports the low tension 
grounding brush 78 provided to relieve the ball 


456 The Automobile Handbook 

bearing of all current which might be injurious. 
Cover 91 also carries the safety cap 89, which 
protects the armature from excessive voltages in 
case the magneto becomes disconnected from the 
spark plugs. 

The distributer consists of the stationary part 
70 and the rotating part 66, which is driven 
from the armature shaft through steel and 
bronze gears 7 and 72. The current reaches this 
distributer from carbon 77 through bridge 84 
and carbon 69. It is conducted to brushes 68 
placed at right angles to each other and making 
contact alternately with four contact plates em¬ 
bedded in part 70. These plates are connected 
to contact holes in the top of the distributer, 
into which the terminals of cables leading to the 
different cylinders are placed. 

In the front plate of the magneto is provided 
a small window, behind which appear numbers 
engraved on the distributer gear which corre¬ 
spond to the numbers marked on the top of the 
distributer. This indicator allows a setting or 
resetting after taking out, without the necessity 
of opening up the magneto to find out where 
the distributer makes contact. Numbers on in¬ 
dicator and distributer show the sequence of 
sparks, not the numbers of cylinders which the 
magneto is firing, as the sequence of firing 
varies with different motors. 

The variation of timing is effected by turn¬ 
ing the magneto proper in the stationary base 
which is accomplished through the spark lever 


The Automobile Handbook 457 

connections attached to one of the side lugs. 
The spark is advanced by turning the magneto 
in the direction of the rotation of the armature. 

If the magneto is defective, the trouble will 
usually be located in the breaker. The plati¬ 
num contacts burn off in time and a readjust¬ 
ment becomes necessary, although this should be 
the case only at very long intervals. The ad¬ 
justment should be such that the breaker begins 
to open with the armature in the position of 
greatest current flow, and that the distance be¬ 
tween contact points when fully open is about 
1/64 inch or slightly more. The small gauge 
attached to the magneto wrench may be used 
for checking this adjustment. The small lock 
nut of the contact screw must be tightened se¬ 
curely after each readjustment of the contacts. 

In addition any oil or dirt reaching the con¬ 
tact points will in time form a fine film which 
prevents perfect short-circuit of the low-tension 
winding. If the condition of these points is 
very bad, or if a complete inspection of the 
breaker is desired, the latter should be removed 
from the breaker box. This can readily be done 
by loosening the long center screw holding the 
breaker to the armature, and screwing it into 
the small tapped hole provided in the breaker, 
so that it may be used as a handle in lifting 
the breaker out. The cleaning of the points 
should be done with a fine crocus paper, or if 
necessary, with a very fine file, after which a 


458 


The Automobile Handbook 


piece of very fine cloth should be passed through 
between the points so as to remove all sand or 
filings. Special care must be taken not to round 
off the edges of the contact points; the satisfac¬ 
tory operation of a magneto depends largely 
upon the perfect contact at this point, and the 
whole surface of the contacts should therefore 
touch. 



Fig. 209 

Inductor Magneto Shaft 


Remy Inductor Magneto. This type of mag¬ 
neto, now so extensively used for ignition pur¬ 
poses, is a comparatively recent product, the 
result of many years of experiment and develop¬ 
ment. The principles of its action are as follows: 
By revolving a solid steel shaft on which are 
two drop-forged steel magnet inductor wings, 
as shown in Fig. 209, the magnetic field is 







The Automobile Handbook 


459 


reversed twice during each revolution, and 
creates two electrical current waves, or im¬ 
pulses per revolution. The direction of flow 
of the magnetic current is changed at each im¬ 
pulse, thereby generating an alternating cur¬ 
rent. A circular shaped stationary winding of 
magnet wire is imbedded between the poles of 



Fig. 210 

Distributor for Inductor Type 

the magnets and around the inductor shaft, 
and a strong current is generated in it and car¬ 
ried directly through the circuit breaking de¬ 
vice by means of heavy lead wires, thus dis¬ 
pensing with the use of carbon brushes and col¬ 
lector rings. 

There are no revolving windings nor mov¬ 
ing contacts, and consequently many sources of 





460 


The Automobile Handbook 


trouble are eliminated. The current is carried 
to the transformer coil located on the dash¬ 
board, where it is stepped up to the high volt¬ 
age necessary for creating the hot jump-spark. 

From the transformer the current is con¬ 
ducted back to a hard rubber distributer, see 



Fig. 211 

Longitudinal Section Through Inductor Type of Magneto 


Fig. 210, on the face of the magneto, and from 
thence to the spark plugs. The distributer 
shaft, located immediately above the inductor, 
revolves a metallic segment past the terminals 
of the wires leading to the spark plugs. The 
high tension current is carried to this segment, 
and transmitted to the spark plug. A magneto 












The Automobile Handbook 461 

of this type, and gear-driven, gives what may 
properly be called perfect timing. A hot spark 
is delivered in the cylinder under compression 
at the exact instant desired. 

The device is also reliable for starting the 
motor from the seat without cranking, for the 
reason that the motor always stops with the 
magneto in such a position that the first spark 
will occur in the cylinder under compression 
and where batteries are used a push button is 
provided, which by merely touching will cre¬ 
ate the spark where needed. Fig. 211 shows a 
sectional view of the magneto. 

An important difference between the Remy 
magneto just described and other models of the 
inductor type is in the handling of the inductor 
weights. In models “RD” and “RL,” each 
inductor wing has been balanced by a bronze 
weight fastened to the magneto shaft and on 
the opposite side of the shaft from the wing 
that it compensates for. The weight, being 
made of non-magnetic material, does not in any 
way affect the operation of the magneto elec¬ 
trically. 

The inductor principle is not used in late* 
models of the Remy magneto, this feature being 
replaced by an armature of the shuttle type 
with a single low-tension winding. A sepa¬ 
rately mounted transformer coil is used with 
these instruments, this coil carrying a switch 
that allows use of the current from the magneto 
armature or from a set of dry cells or storage 


462 


The Automobile Handbook 


battery, the current, from whichever source, 
passing though the same breaker, coil, distribu¬ 
tor and plugs. 

The breaker of the new models is composed of 
a steel cam mounted upon and turning with the 
armature shaft and which strikes against a 
contact piece in a pivoted arm that carries one 
of the contacts of the breaker. Except for the 



Breaker Mechanism of Remy “RD” Magneto 

movement required in altering the time of the 
spark, the contacts and the pivoted arm remain 
stationary, the cam being the only revolving 
part of the breaker mechanism. The condenser 
that is attached between the breaker contacts is 
carried in a housing that is mounted above the 
magneto armature and between the magnet legs. 
See Fig. 212. 




Wiring of Remy Magnetos 


The Automobile Handbook 463 

A device, known as a timing button, is incor¬ 
porated on the Models “P,” “30,” “31” and 


g 

£5’ 

to 

CO 


*-d 


p 

3 

P* 


co 

to 






“32” Remy magnetos, for the purpose of tim¬ 
ing the magneto in connection with the engine. 






































464 


The Automobile Handbook 


To set the magneto turn the engine crankshaft 
until the piston of No. 1 cylinder is at top cen¬ 



ter after the compression stroke. Press in on 
the timing button at the top of the distributor 


Fig. 214 

Wiring of Remy Magnetos “30” and “31 1 



























































The Automobile Handbook 465 

and turn the magneto shaft until the timing but¬ 
ton is felt to drop into the recess on the dis¬ 
tributer gear. With the magneto in this posi¬ 
tion, make the coupling with the engine without 
paying any attention to the position of the 
breaker cam. The location of the distributer 
terminal for the plug in No. 1 cylinder is deter¬ 
mined by the direction of rotation of the mag¬ 
neto. If the magneto runs clockwise, No. 1 ter¬ 
minal is at the lower left hand corner of the dis¬ 
tributer, while for anti-clockwise drive No. 1 
terminal is at the lower right hand corner. The 
wiring for the Models “P” and “32” is shown 
in Fig. 213, while the connections for Models 
“30” and “31” are shown in Fig. 214. 

Simms Magneto. The armature is of the true 
high-tension type, on which is wound both the 
low-tension primary and high-tension secondary 
windings, connected in series. The magneto 
generates a high-tension current directly in the 
armature, and does not use an exterior coil or 
other device to step-up or transform the cur¬ 
rent. 

A safety spark gap is provided to prevent 
damage to the magneto, in the event of one or 
more of the high-tension cables becoming dis¬ 
connected from the spark plugs. This gap is 
so located that its action may be readily ob¬ 
served for the purpose of locating the cause of 
possible misfiring. 

The model “SUD” consists of a dual system 
in which is provided a small lion-vibrating coil 


466 


The Automobile Handbook 


which can be either attached to the frame or 
dash of car, as the coil is unaffected by either 
moisture or heat. 

The switch operating the battery circuit is in 
connection with the starting switch and when 
the starting pedal is depressed (thereby throw¬ 
ing the starting motor into operation) the cur¬ 
rent flows through the switch coil and magneto. 



Magnets and Extended Pole Pieces of Simms 
Magneto 

As soon as the engine starts, or the starting 
pedal is released, the circuit is automatically 
disconnected, and the engine runs on the mag¬ 
neto. One of the principal features of the 
Simms magneto is the extended pole shoe, shown 
in Fig. 215. 














The Automobile Handbook 


467 


To time the magneto to engine: Turn the 
engine over by the starting crank until No. 1 
piston reaches top dead center on compression 
or firing stroke. Remove the dust cover, or if 
a dual magneto, the commutator, and turn the 
armature shaft until the figure 1 appears in the 
“sight-hole” of distributor, Fig. 216. This 
shows that that distributor brush is in contact 



with distributor post 1. Retard the contact 
breaker and move the armature, either to the 
right or left, as occasion requires, until the plat¬ 
inum points just break, or, in other words, just 
separate. With the magneto in this position 
couple it to the engine (to dead center on com- 











468 


The Automobile Handbook 


pression stroke), and connect the remaining ter¬ 
minals up in the proper firing order of the 
engine. 

For timing the model S U D, proceed as 
above. The above instructions relative to en¬ 
gine position apply also in this instance. The 
only change is as follows: 

For locating the position of the carbon brush 
on No. 1 distributer segment, remove the dis¬ 
tributer, which is held in place by means of two 
spring clips, and turn the armature shaft until 
the distributer brush is brought into position, 
namely, opposite No. 1 segment. 

If the magneto is not firing, try the follow¬ 
ing test. While the motor is running, discon¬ 
nect one of the high tension cables from spark 
plug, being careful not to touch the metal ter¬ 
minal, and hold the cable with the terminal 
close, about to 3/16", to any part of the 
motor. This will show the strength of the spark 
and each cable may be tested in turn. If the 
magneto is not delivering a good spark, examine 
the contact breaker. The break or gap between 
the platinum points, when open due to the cam 
action, should correspond to the thickness of the 
gauge furnished, which is approximately .015. 

Splitdorf Magneto. The system used in old¬ 
er models is that having an armature with but 
one winding, and giving a current of compara* 
tively low tension. The current is discharged 
through a transformer having a low and a high- 
tension winding somewhat similar to regular 


The Automobile Handbook 


469 


spark coil. This steps the current up to a volt¬ 
age sufficiently high to enable it to jump the 
necessary gap between the points of a spark 
plug in the compressed mixture in the cylinder 
of the motor. 

The plain H, or shuttle, armature is mounted 
between two annular ball bearings, Fig. 217. 
One end of the shaft is the driving end and the 
other is equipped with the breaker cam and the 



Fig. 217 

Section Through Splitdorf Magneto 

insulation plug which delivers the current gen¬ 
erated in the armature to the collector brushes 
from which it is transmitted to the transformer 
connection. 

From A, Fig. 218, the armature current goes 
through the primary of the transformer, return¬ 
ing through the binding post No. 2 to the con¬ 
tact screw bracket on the breaker box. No. 3 is 
a common ground connection for both the mag¬ 
neto and transformer. The circuit being broken 





























470 


The Automobile Handbook 


at the proper moment, a very high voltage cur¬ 
rent is induced in the secondary winding of the 
transformer, and being delivered to the heavily 
insulated cable D, is conducted to the central 
brush of the distributor, whence it is delivered 
to the spark plugs in the different cylinders in 
correct sequence. 



In addition to using the current from the 
magneto, the transformer may be used as a 
spark coil by using the breaker mechanism of 
the magneto in the circuit to interrupt a cur¬ 
rent from the battery, which can be switched 
in for starting purposes or for an emergency. 
The distributor is used to deliver the current 
thus generated to the spark plugs. This gives a 
dual system with one set of spark plugs, and 
the movement of the switch controls both sys¬ 
tems. Fig. 219. 





























The Automobile Handbook 471 

A later development is the new standard 
“T S” type of transformer, Fig. 220, which 
has practically superseded all other types, par- 



Fig. 219 

Wiring of Splitdorf Magneto With Transformer 
Coil 

ticularly as it does away with the separate 
switch and still leaves the dash free. Both leads 
from the battery must run direct to transformer. 


To Plugs 



Wiring of Splitdorf Magneto With Tubular Coil 


















































472 The Automobile Handbook 

After securing the magneto to the prepared 
base on the motor, crank it until cylinder No. 

1 is exactly on its firing center (i. e., the point 
of greatest compression. The motor must re¬ 
main in this position until the balance of the 
work is finished. 

Retard the spark advance mechanism at the 
steering wheel to its limit and connect it to the 
spark advance lever on the breaker box of the 
magneto, so that if the magneto shaft revolves 
in a clockwise direction looking at the driving 
end, the breaker box lever will be at its top¬ 
most position. If the shaft revolves left-handed 
the lever should be at the bottom limit, and ad¬ 
vanced upward. 

Now revolve the armature shaft in its direc¬ 
tion of rotation until the oval breaker cam 
comes in contact with the roller in the breaker 
bar and begins to separate the platinum contacts. 

If it is desired to start on the magneto side, 
ignoring the battery entirely, advance the spark 
mechanism about one-half or two-thirds of the 
way and crank as before. No back kick should 
be observed. Do not drive the motor with the 
spark retarded, but as far advanced as the 
motor will permit. 

If the platinum contacts after much usage 
become pitted so that a bad contact results, 
they can be filed flat with a fine file, taking 
care not to file off any more than is necessary. 
Then reset the screw so that the break is not 
more than -025 of an inch. 


The Automobile Handbook 473 

Don’t forget to occasionally brush the dis- 
* ributer disc and interior of distributer block 
clean of any accumulation of carbon dust. 

The “E U” magneto is a new high tension 
machine designed for four cylinder motors de¬ 
veloping as high as 40 horse power. 

The construction of this magneto embodies 
an aluminum base to which the pole pieces are 
secured, and between which revolves an arma¬ 
ture on two annular ball bearings. The circuit 
breaker is attached to one end of the armature 
shaft and revolves with it. The magneto is 
self-contained, having both a primary and sec¬ 
ondary winding on the armature. 

The high tension winding of the armature is 
connected to a collector ring, imbedded in a 
spool mounted on the driving end of the arma¬ 
ture shaft. From this ring a carbon brush leads 
the current through a water-proof holder to the 
center of the distributer disc. 

The cam holder may be shifted to the extent 
of 30 degrees, enabling an advance or retard of 
the spark to be obtained, thereby causing igni¬ 
tion to take place earlier or later. 

The condenser necessary for the protection of 
the platinum points and the proper functioning 
of the machine is placed in the driving head of 
the armature and revolves with it. 

The distributer consists of a disc of insulating 
material having a metal segment to which the 
high tension current is led from the collector 
brush. The distributer block has four small 


474 


The Automobile Handbook 


carbon pencil brushes which lead the current to 
the brass connection imbedded in the block, to 
which the plug wires are fastened. The posi¬ 
tion of the segment on the disc can be seen 
through the little window in the face of the 
distributer block for the purpose of setting the 
machine when timing. 

A spark gap for the protection of the arma¬ 
ture winding is located at the inside end of the 
brush holder under the magnets. 

The main bearings of the magneto are pro¬ 
vided with oil cups, and a few drops of light 
oil every 1,000 miles are sufficient to lubricate 
them. The breaker arm should be lubricated 
with a drop of light oil applied with a toothpick 
to the hole in the bronze bearing pivoted on 
the steel pin. The cams are lubricated by a felt 
packing, and a little oil applied to the holes in 
the edge of the cams will last a long time; any 
surplus oil should be removed and care taken 
to prevent any oil getting on the platinum 
points. 

The proper distance between the platinum 
points when separated should be .020 or 1/50 of 
an inch. A bronze gauge of the proper size is 
attached to the wrench furnished for the adjust¬ 
ment of the platinum screw and lock nut. 

The fibre roller on the end of the breaker arm 
is held in position by a pawl spring. The wear¬ 
ing surface of the roller may be renewed by 
rotating the same a quarter turn, thus bringing 
a new surface to bear on the cam, and as there 


The Automobile Handbook 


475 


are four slots in the roller four wearing surfaces 
are available. 

To time the magneto, rotate the crank shaft 
so as to bring the piston No. 1 cylinder 1/16 
of an inch ahead of the upper dead center of 
the compression stroke. With the timing lever 
fully retarted, the platinum points of the cir¬ 
cuit breaker should be about to separate. Some 
motors may require an earlier setting. 

The distributor segment should show in the 
little window in the block and the plug wire to 
No. 1 cylinder should be fastened under the 
brass nut directly over the segment. The rest 
of the plug wires should be fastened in turn 
according to the proper sequence of firing of 
the cylinders to which they lead. 

U and H Magneto. The particular feature of 
this magneto, is that the starting spark is a 
maximum, whether the crank is turned slowly 
or fast. 

In the operation of the U and H magneto, 
Fig. 221, a low-tension current of electricity is 
generated by the rotation of the armature of 
the magneto. An interrupter, or timer, inter¬ 
rupts the flow of this low-tension current at the 
proper time, this interruption causing a high- 
tension current, similar to that delivered by the 
induction coil of a battery ignition system, to 
be induced in the rotating armature by a pe¬ 
culiar arrangement of the windings of the arma¬ 
ture. The high-tension current is conducted to 
a so-called distributer, the duty of which is to 


476 


The Automobile Handbook 


distribute the high-tension current to the spark 
plugs of the various cylinders in the proper se¬ 
quence of firing. The wiring diagram of the U 
and H magneto is shown in Fig. 222. 



Fig. 221 

U. & H. Magneto 


The magneto consists of three pairs of per¬ 
manent horseshoe magnets, placed parallel, 
and having secured to each of their free ends 
a soft iron block. These blocks are exactly 





























































The Automobile Handbook 


477 


alike, and form a permanent magnetic field. 
They are bored so as to allow an armature to 
revolve between them. The armature is of the 
shuttle type, and is provided with a double 



winding. The inner or primary winding con¬ 
sists of a few layers of coarse insulated wire. 
The outer or secondary winding consists of a 
great number of layers of fine insulated wire. 
The beginning of the primary winding is 

































478 


The Automobile Handbook 


grounded to the armature itself. The end of 
the primary winding is connected with the 
carbon brush 1, which is carefully insulated 
from the armature shaft. Brush 1 bears against 
the interrupter block screw 2, which in turn 
conducts the current to the interrupter block 3, 
and to the condenser plate 4. From the inter¬ 
rupter block 3 the current is conducted by 
means of the platinum pointed interrupter con¬ 
tact screw 5 to the platinum contact on the 
interrupter lever 6. The interrupter lever 6 
has metallic contact with the body of the mag¬ 
neto, and is therefore grounded and in elec¬ 
trical connection with the beginning of the pri¬ 
mary winding. It will be seen that when the 
interrupter lever 6 is in contact with interrup¬ 
ter contact screw 5, the primary circuit is 
closed, and the primary winding of the arma¬ 
ture is short-circuited. 

The beginning of the secondary winding is 
connected to the end of the primary winding, 
being in fact a continuation of the primary 
winding. This fact should be borne in mind, 
as it has direct bearing upon the results at¬ 
tained with this magneto. The end of the sec¬ 
ondary winding is connected to the armature 
slip ring 7, which is thoroughly insulated from 
the armature. From the armature slip ring 7 
the current is conducted by means of the 
brushes 8-8 to the distributer slip ring 9, from 
whence it is led to the distributer brush 10 by 
means of the distributer brush spring seat 12. 


The Automobile Handbook 


479 


The distributer plate 13 is provided with as 
many brass distributer segments 14, evenly 
spaced around the distributer bore, as there are 
cylinders to be fired, and as the distributer 
brush is revolved it comes into contact in suc¬ 
cession with the segments. These segments are 
in turn connected with the secondary terminals 
15, located at the top of the distributer plate, 
one terminal for each cylinder. From these 
terminals the high tension current is conducted 



Fig. 223 

U. & H. Magneto Interrupter 


by cables to the spark plugs of the cylinders, 
from whence, after jumping the gap it is con¬ 
ducted to the grounded end of the primary coil, 
through the primary coil to the beginning of 
the secondary winding, thus completing the sec¬ 
ondary or high tension circuit. 

U and H Interrupter. The interruption of 
the primary circuit is accomplished by the in¬ 
terrupter, as shown in Fig. 223. This device 
consists of the interrupter plate 16, which is 






480 The Automobile Hcmdbook 

located in the interrupter 17. Attached to the 
interrupter plate 16 is a stud 18, Upon which 
is pivoted the. interrupter lever 6. The inter¬ 
rupter lever is provided with a platinum 
pointed contact screw 19, which is normally 
held by the flat spring 20 in contact with the 
platinum pointed interrupter contact screw 5. 
The interrupter contact screw 5 is connected to 
the end of the.primary winding, as already de¬ 
scribed. 

Keyed to the interrupter end of the armature 
shaft, and rotating positively with the arma¬ 
ture, is the interrupter cam housing 21. Se¬ 
curely attached to the interrupter cam housing 
is the interrupter cam 22, consisting of a ring 
of hard fiber, having on its inner face two pro¬ 
jections or cam faces 22A. 

The interrupter housing 17 is held in accu¬ 
rate alignment with the interrupter cam 22 by 
the construction of the rear end plate 23, and 
as the armature revolves the projections 22A- 
22A are brought into contact with the interrup¬ 
ter cam pin 24, causing a movement of the in¬ 
terrupter lever 6 sufficient to separate the con¬ 
tact screws 5-19, and thereby interrupt the pri¬ 
mary circuit twice in every revolution. As the 
projections 22A continue to revolve, the inter¬ 
rupter lever 6 instantly resumes its normal po¬ 
sition, and completes the primary circuit. The 
entire housing of the interrupter is easily re¬ 
moved for inspection, or adjustment by push¬ 
ing the spring clip 31 to either side. 


The Automobile Handbook 


481 


Induction Coil. The form of coil generally 
used on gasoline cars is known as the jump- 
spark coil. It is of two types, one known as a 
plain or single jump-spark, the other as a vi¬ 
brator or trembler coil. 

A jump-spark coil consists essentially of a 
bundle of soft iron wire, known as the core, 
over which are wound several layers of coarse 
or large size insulated copper wire, called the 
primary winding. Over this are again wound 
a great many thousand turns of very fine or 
small wire, known as the secondary winding. 

Inertia. Inertia is that property of a body 
by which it tends to continue in the state of 
rest or motion in which it may be placed, until 
acted upon by some force. As used by the non¬ 
technical, it is almost universally employed in 
the former sense, i. e., that of the resistance 
which a body offers against a change in its po¬ 
sition, an inert body usually being intended, so 
that the definition is perfectly correct so far 
as it goes. The popular impression is that only 
inert bodies have inertia, it being likewise gen¬ 
erally thought that a moving body is possessed 
of momentum alone, whereas an object at rest 
is possessed of inertia, and the same object in 
movement has both momentum and inertia. 

Insulating Material. Asbestos, lava, and mica 
are severally used for the insulation of spark 
plugs and sparking devices. 

Vulcanized fiber or hard rubber or even hard 
Wood are used for the bases of switches, con- 


482 The Automobile Handbook 

nection boards and other places. 

India rubber, or gutta-percha form the basis 
of the insulated covering of wires used for elec¬ 
trical purposes. The coils of small magnets and 
the cores of induction coils are usually wound 
with cotton covered wire, or in some instances 
the fine wire is silk covered, as in the case of 
secondary or jump-spark coils. 

Joints, Ball and Socket. To produce a flexible 
joint capable of operation within certain limi¬ 
tations in any direction, the ball and socket 
form of joint is generally used on the ends of 
the rod which connects the arm of the steering 
mechanism with the steering lever attached to 
the hub of one of the steering pivots of the 
front axle. 



distortion of the frame or running gear of an 












































The Automobile Handbook 483 

automobile, due to unequal spring deflection 
and irregularities of the road surface, means 
should be provided to insure flexible joints or 
connections between the various rotating parts 
of the mechanism of a car. The device shown 
in Figure 224 is not susceptible to any great 
amount of angular distortion, but will transmit 
power with a practically uniform velocity, with 
the axes of the shafts considerably out of align¬ 



ment in vertical or horizontal parallel planes. 

The form of compensating joint shown in 
Figure 226 may be operated with the axes of 
the shafts at an angle to each other, or with the 
shafts out of alignment with each other in ver¬ 
tical or horizontal parallel planes, and has quite 
a range of operation with either condition. Both 





























484 


The Automobile Handbook 



forms of the device require to have bearings on 
either side, as shown, to insure their proper 
working. 


































































/- 















































, '' 




















































• • 












































































































































































































































































































































































































































































































































































































